\NUFACT1 ANDARD SPECIFICATION STRENGTHENING AND WATERTIGHTZNINCi CEMENT MORTARS AND CONCRETE PRACTICAL APPLICATION USE IN MORTARS BYE.W.LAZELL, PH.D. .Engineering T ^ UNIVERSITY OF DEPARTMENT OF CIVIL ENGINEERING BERKELEY, CALIFORNIA Illlllllll Illlllllllllll IIIIUIIMIIIIIIIIIIIMIIIIM = I 1 Hydrated Lime I Illlllllllllllllllllllll lililllllf? = .11 History, Manufacture and Uses in Plaster - Mortar - Concrete 1915 A Manual For The Architect, Engineer, Contractor and Builder. By E. W. LAZELL, Ph. D. Member American Institute of Chemical Engineers. Member American Society Mechanical Engineers. Member American Society for Testing Materials. I I I = = = = = I EE I ^ i = i = i = E == I 1 = = Engineering Library Copyright 1915 by E. W. LAZELL, Ph. D. PUBLISHED BY JACKSON-REMLINGER PTG. CO. PITTSBURGH, PA. CHAPTERS Chapters Page Introduction 7 I Historical 9 II Chemistry of Lime 11 III Classification of Lime 21 IV Manufacture of Lime 24 V Slaking Lime 34 VI Manufacture of Hydrated Lime 41 VII Properties of Hydrated Lime 46 VIII Use of Hydrated Lime in Sand Mortars 49 IX Use of Hydrated Lime in Concrete 63 X Advantages of Hydrated Lime over other forms of Lime .... 79 Appendix I Useful Data 81 Appendix II Standard Specifications for Hydrated Lime. . . 84 Appendix III Quantities of Materials for One Cubic Yard of Plastic Mortar . 87 LIST OF ILLUSTRATIONS Page Pyramid of Cheops Frontispiece Lime Cycle 17 Pot Kiln 25 Field Kiln 26 Draw Kiln 27 Vertical Steel Kiln 28 Vertical Steel Kiln, With Stack 29 Vertical Producer Gas Kiln 32 Modern Installation of Lime Kilns Equipped to Use Producer Gas 33 Clyde Hydrator 43 Kritzer Hydrator 44 Second National Bank Building, Toledo, Ohio 51 Equitable Building, New York City 61 Leader-News Building, Cleveland, Ohio 64 Dam, White Salmon River, State of Washington (Under Construc- tion) 65 Dam, White Salmon River, State of Washington (Completed) .... 67 Concrete Road, Garret Co., Maryland 68 Armory, York, Pa 69 Reservoir, Waltham, Mass 72 Ambursen Hollow Dam, Portland, Ore 76 Hotel Oregon, Portland, Ore 78 821018 INTRODUCTION IN presenting this book to the public, the purpose has been to direct the attention especially of architects and builders to the comparatively new form of lime "Hydrated Lime," which possesses many advantages over the older Lump Lime. The art of using lime is one of the very oldest connected with the building trade and was probably brought to its greatest perfection by the Greeks and Romans. Since these ancient times until very recently little or no improvement has been introduced in the preparation of plaster or stucco made from lime. Probably the reason for this is the time and care required to slake the lump lime used to prepare the mortar. With the use of hydrated lime the time required to slake and age the quick lime is done away with. It has been my aim to collect together in convenient form the available data on this subject. Use has been made of previous publications and much information has been ob- tained from the technical press. Especial mention must be made of the works of Vitruvius, Vicat, Miller and Hodgson and the various publications of the different Bureaus of the United States Government. It is hoped that the book may prove useful in calling attention to the characteristics of hydrated lime and describing its various uses. 1915 E. W. LAZELL, Ph. D. HISTORICAL CHAPTER I r I "MIE use of lime as a binding material or mortar for holding together stone and brick originated in the remote past. It is probable some savages, having used stones composed of limerock to con- fine their fire, noticed that the stones were changed by the action of the heat. A passing shower slaked the lime to a paste, thus the dis- covery was made that the paste was smooth working and furnished a better material than clay to fill up the holes and crevices in their crude dwellings. From the discovery of the fact that burned limerock gave a material which slaked with water to a paste, it was but a step to the addition of sand in order to produce a mortar. The art of using mortar in some form or other is as old as the art of building or as civilization itself. Evidences of the use of mortar are found not only in the older countries of Europe, Asia and Africa, but also in the ruins of Mexico and Peru. The remains of the work of these ancient Artisans are evidence to us of the enduring qualities of lime mortar as well as the skill and knowledge possessed by the user. Miller in his work on mortar states "Plastering is one of the earliest instances of man's power of inductive reasoning, for when men built they plastered; at first, like the birds and beavers, with mud; but they soon found out a more lasting and more comfortable method, and the earliest efforts of civilization were directed to plastering. The inquiry into it takes us back to the dawn of social life until its origin becomes mythic and pre- historic. In that dim, obscure period we cannot penetrate far enough to see clearly, but the most distant glimpses we can obtain into it shows us that man had very early attained almost to perfection in compound- ing material for plastering. In fact, so far as we yet know, some of the earliest plastering which has remained to us excels, in its scientific com- position, that which we use at the present day, telling of ages of experi- mental attempts. The pyramids of Egypt contained plaster work executed at least 4000 years ago, and this, where wilful violence has not disturbed it, still exists in perfection, outvying in durability the very rock it covers, where this is not protected by its shield of plaster." The earliest known examples of the employment of mortar in masonry are presented by the pyramids of Egypt. Vicat in his cele- brated treatise on Mortars and Concrete, states: "The Egyptian monuments present without doubt the most ancient and remarkable examples which we can quote of the use of lime in building. The mortar which binds the blocks of the pyramids, and more particularly those of Cheops, is exactly similar to our 'mortars in Europe. That which we find between the joints of the decayed buildings at Ombos, at Edfou, in the Island of Phila, and in other places, gives evidences by its color, of a reddish very fine sand mixed with lime in the ordinary proportion. The use of cements (limes) was therefore already known two thousand years before our time; perhaps it would be easy to carry that epoch still farther back, were we to consult the ancient monuments of India, and the Sanscrit books, if they speak of the ancient relations of Egypt with that country; but this would be to attach too much importance to an inquiry, more curious than useful." At a very early period the Greeks used plaster consisting of a true lime stucco of most exquisite composition, thin, fine and white. The houses of the simple citizen were ornamented with stucco which for whiteness, hardness and polish compared well with the Parian marble. Thus at the time of Pericles and Plato, the art of plastering had made great progress. From the Greeks the Etruscans, of middle Italy, gained their knowledge and the Romans in turn learned the art of plastering from them. Greece became a Roman province in 145 B. C., and the loot of it gave a great impetus to Roman art. Our knowledge of the Roman methods of building and their use of material is largely derived from the writings of Vitruvius. Vitruvius was a military engineer under Julius Ceasar in his African campaign and was an architect under Augustus. On all matters relative to Greek and Roman architecture, Vitruvius should be consulted, since according to his own confession his work contained all the knowledge that the Greeks possessed of the art of building. Pliny the elder, in his natural history, and Palladius, have added nothing to what Vitruvius had said before them. The writings of Vitruvius will be referred to later in other chapters, since his monumental work on architecture remained a standard refer- ence book until well into the 18th Century. The Arabians and Moors both became experts in plastering as is evident by the splendid plaster work still to be seen on the Alhambra. As early as the beginning of the 16th Century, the art of plastering had made considerable progress in England and "The Plasterers Com- pany*' was incorporated in 1501. This brief review of the art of plastering as practiced by the Ancients, will give an idea of the possibilities of the use of lime as well as proving its enduring qualities. It is indeed sad to state that the present status of the art does not nearly reach the perfection attained by the Greeks and Romans, and it is with a wish to interest the public in the various uses of lime mortar that this treatise was undertaken. 10 CHEMISTRY OF LIME CHAPTER II ANY change which alters the composition and structure of matter is a chemical change. A familiar illustration of this is the burning of coal in which case both the composition and structure are changed. It therefore follows since the structure and composition of lime are changed by burning that a chemical reaction has taken place. If the changes brought about by burning and slaking lime are to be understood some knowledge of chemistry is necessary. From a chemical standpoint, the changes which take place in the manufacture of lime from limestone and the subsequent changes in slaking and hardening are comparatively simple and do not involve an extended knowledge of chemistry. In order to render the subject clear, the various chemical terms involved will be explained and denned. All matter is made up of one or more elementary substances, or chemically speaking, all matter is made up of one or more elements. An element is a primary form of matter which cannot be reduced to a simpler form by any means known to science. There are some 80 of these elemen- tary forms of matter known, and of these only about a dozen are involved in the chemistry of lime. These elementary substances combine with each other forming compounds in a certain known definite manner. Thus a compound is the product resulting from the union of two or more dis- similar elements. Modern science recognizes three divisions of matter, Mass, Molecule and Atom. Mass alone is appreciable to the senses. The other divisions being far too minute to be reached by any power of observation. Mole- cule is the term used to designate the smallest particle of matter that can exist and still preserve the properties of the substance. It is formed by a union of atoms which may be like or unlike, few or many ; it is constant and regular in the disposition of its parts and bound together by strong forces. The use of the term "atom" is from theoretical rather than experimental considerations. Experiment has shown that a definite quantity of each element always enters into combination, and theory assumes that the smallest quantity entering into any combination is an "atom." An atom can be defined as the smallest part of an element that can enter into combination with another element. 11 Although the atom in all cases is too small to be weighed individually, the relative weight of each kind of atom has been carefully obtained as the result of experiment. The weights of the various atoms have been determined relatively by comparing them with hydrogen (the lightest known element) which is taken as unity or one. These relative weights arc called the "Atomic Weights." TABLE No. 1 Atomic weights of the common elements Name Chemical Symbol Atomic Weights Hydrogen H 1 Oxygen O 16 Carbon C 12 Calcium Ca 40 Magnesium Mg 24 Aluminum Al 27 Iron (ferrum) Fe 56 Silicon Si 28 Sulphur S 32 NOTE The atomic weight is given to the nearest whole number as this is sufficiently accurate. The atomic weight of an element means that the weight of its atom is so many times heavier than the weight of an atom of hydrogen. For example, the weight of an atom of oxygen is 16 times greater than that of an atom of hydrogen. For convenience abbreviations are used for all elements. These abbreviations are known as Chemical Symbols. Chemical Symbols serve not only as an abbreviation for the name of the element, but the chemist employs them to indicate the composition of the compound and the number of atoms of the element in the compound. Thus the symbol for calcium carbonate is written CaCO 3 . In which "Ca" stands for calcium, "C" for carbon and "O" for oxygen. The symbol further indicates that there is present in each molecule of calcium carbonate one atom of "Ca," one atom of "C" and three atoms of "O." If the atomic weight of the elements are inserted in the place of the symbol, we have Ca = 40, C = 12, O = 16, O 3 = 48, total 40+12+48 = 100, the molecular weight of calcium carbonate. The molecular weight of a com- pound therefore is the sum of the weights of the atoms making up the com- pound. Knowing the molecular weights of a substance arid the elements of which it is composed, it is possible to calculate its percentage W composition. As an illustration, take calcium carbonate, the percentage of each element present is: Ca 40/100 = 40% C 12/100 = 12% O 48/100 = 48% Calcium carbonate can also be considered as composed of calcium oxide (CaO) and carbon dioxide (CO 2 ). Calcium oxide (Ca+O) 40+16= 56 Carbon dioxide (carbonic acid gas) (C+O 2 ) 12+32= 44 100 Therefore, there is present in calcium carbonate: 56/100 = 56% CaO (lime) 44/100 = 44% CO 2 (carbon dioxide) The compounds of the above elements most useful to the student of lime are the oxides, hydroxides, hydrates and carbonates. These various compounds of the elements given in Table No. 1 are illustrated in Table No. 2. TABLE No. 2 Elementary Substance Union of Two or More Elementary Substances or Element or Compounds With Oxygen Oxides With Water Hydroxides Hydrates With Carbon Dioxide Carbonates Name c 1 i Name C/3 3 _b 1^ Name I Molecular Weight Name V) Molecular Weight Hydrogen TT i Water H 2 O 18 Oxygen O 16 Carbon c 12 / Carbon \ Dioxide C0 2 44 Calcium Ca 40 ( Calcium | Oxide ( Lime CaO 56 Calcium Hydroxide Ca(OH) 2 74 Calcium Carbonate CaCO 3 100 Magnesium M 24 C Magn'm j Oxide (. Magnesia MgO 40 Magnesium Hydroxide Mg (OH) 2 58 Vlagnesium Carbonate M g C0 3 84 Aluminum Al 27 ( Alumn'm j Oxide (. Alumina A1 2 3 102 Aluminum Hydroxide A1 2 (OH) 6 156 Iron(Fermm) Fe 56 f Ferric I Oxide Fe 2 3 160 Ferric Hydroxide Fe 2 (OH) 6 214 Iron Fe 56 ( Ferrous I Oxide FeO 72 Ferrous Hydroxide Fe(OH) 2 90 ( Silicon Silicon Si 28 \ Oxide SiO 2 60 1 Silica Sulphur s 32 f Sulphur \ Dioxide S0 2 64 13 BURNING The chemical change which takes place in burning lime consists in destroying the bond between the calcium oxide and carbon dioxide. This change is illustrated by 'using the chemical symbols in the form of an equation and for a perfectly pure calcium carbonate the chemical change can be illustrated as follows: Calcium carbonate + heat = calcium oxide + carbon dioxide (limestone) (lime) (gas) CaCO 3 +heat = CaO +CO 2 100 + heat = 56 +44 This equation shows that the calcium carbonate has been broken up into two dissimilar substances by the action of heat, one of which is a solid (lime) and the other a gas (carbon dioxide) . Further, it indicates that 100 parts by weight of calcium carbonate yield 56 parts by weight of lime, and that 44 parts by weight of carbon dioxide are driven off by heat. In the change produced by burning, the gas (carbon dioxide) is carried out of the kiln together with the products of combustion of the fuel. Nothing but the carbon dioxide is removed, except any moisture or organic matter which may have been present in the stone. The solids, lime, magnesia and all other substances, remain in the burned lime. If the limestone contained 5% of impurities, such as silica or clay, these would have remained in the burned product. In this case in 100 parts of the impure stone there would be 95 parts of calcium carbonate. These 95 parts of calcium carbonate would yield 95/100X56 = 53.2 parts of calcium oxide, the total matter remaining after burning would be 53.2+5 or 58.2 parts of impure lime, since the 5 parts of impurities can- not be removed by burning. The percentage composition of the burned lime would be: 53.2 = 91.4% calcium oxide 58.2 is 8.6% impurities 58.2 The presence therefore of 5% of silica or clay in the original limestone has reduced the amount of lime (calcium oxide) in the burned product from 100% to 91.4% or nearly 9%. In a similar manner the burning of a dolomitic limestone may be illustrated as follows: 14 Dolomite -f- heat = Dolomitic lime Calcium and magnesium carbonate +heat = calcium and magnesium oxide +carbon dioxide CaCO 3 , MgCO 3 +heat = CaO, MgO + 2CO 2 100 84 (184) +heat= 56 40 (96) + 88 The percentage composition of the dolomitic lime would be as follows : 56 - = 58.34% Calcium oxide (CaO) i/O 40 = 41.66% Magnesium oxide (MgO) yo One hundred and eighty-four pounds (184 Ibs.) of dolomitic lime- stone yield 96 Ibs. of dolomitic lime or 52.17% (96 -=-184 = 52.17%): that is 100 Ibs. of dolomite yields only 52.17 Ibs. of dolomitic lime, con- sisting of the oxides of calcium and magnesium. From the preceding equations it will be seen that the amount of impurities present in the stone increased the yield of the burned product, although at the same time it decreased the amount of oxides of calcium and magnesium present in the burned material (5 Ibs. of impurities present in the stone decreases the amount of the oxides of calcium and magnesium contained in the burned product to about 91%). Further it will be noted that 100 Ibs. of dolomitic limestone gave only 52.17 Ibs. of burned material, while 100 Ibs. of high calcium limestone gave 56 Ibs. of burned material, thus the presence of magnesia decreases the yield from 100 Ibs. of stone. SLAKING OR HYDRATING LIME As is well known, when quick-lime is treated with water, heat is generated and a product is formed which has an entirely different char- acter than the original quicklime. This indicates that a chemical reac- tion has taken place which can be expressed for the two groups of limes as given below: High calcium quicklime + water = high calcium hydrate CaO +H 2 =Ca(OH) 2 56 +18 =74 In this reaction 56 parts by weight of high calcium quicklime have combined with 18 parts by weight of water producing 74 parts by weight of dry hydrate. This dry hydrate contains the original amount (56 parts) of quicklime, but this material is not present as quicklime since 15 it has chemically combined with the water. In case more than the exact amount of water necessary to form the chemical hydrate is present, this water is simply mechanically mixed with the hydrate forming a lime paste. Calcium oxide is the only compound present in the lime which actively combines with water, in the ordinary methods of slaking. For dolomitic quicklime the reaction of slaking is expressed by the following equation: Dolomitic quicklime + water = Dolomitic hydrate CaO MgO +H 2 =Ca(OH) 2 MgO 96 +18 = 114 By comparing this equation with the one for high calcium quick- lime it will be noticed that less water has been combined in the slaking. The reason for this is that the magnesium oxide contained in dolomite is rendered inert at the temperature of burning and does not combine chemically with the water, but remains present in the hydrate as mag- nesium oxide. Thus dolomitic hydrate consists of a mixture of calcium hydrate and magnesium oxide. It is for this reason that it requires a greater weight of dolomitic quicklime to produce the same weight of hydrate. The amount of caustic oxides present in the dolomitic hydrate is greater than in the high calcium hydrate. The above equation was calculated for a pure dolomite containing 58.5% lime and 41.5% magnesia. HARDENING The hardening of lime mortar is due to the lime and magnesia present in the mortar combining with the carbon dioxide of the atmosphere. The chemical change that takes place can be illustrated by the following equation: Calcium hydrate + Carbon dioxide = Calcium carbonate + water Ca(OH) 2 + CO 2 =CaCO 3 +H 2 O 74 +44 =100 +18 Magnesium oxide + Carbon dioxide = Magnesium carbonate MgO +C0 2 =Mg CO 3 40 +44 =84 From the foregoing explanation, it will be seen that lime passes through three distinct chemical phases in its change from the stone to the hardened mortar. These three phases form a cycle, and in the end lime has returned to its original form. These three changes have been illustrated and are given below: 1st Burning CaCO 3 +heat = CaO + CO 2 2nd Slaking CaO +H 2 O = Ca(OH) 2 3rd Recarbonating (hardening) Ca(OH) 2 +CO 2 =CaCO 3 +H 2 () These changes have been graphically illustrated by the author as the "Lime Cycle." Page No. 17. 16 LIME|CTCLE Showing the Sequence of the Changes Produced by Burning, Slaking and Hardening, and that these Changes Form a Complete Cycle; the Lime Returning to its Original Carbonate Form. Copyrighted, E. W. Lazell, 1911 17 A familiarity with the chemical terms and the changes which take place in the manufacture and use of lime has a further advantage both to the manufacturer and user in that it renders easy the interpretation of the results of a chemical analysis of limestone and lime. This can best be explained by starting with the analysis of a natural sample of lime- stone and dolomite and following the two cycle change produced by burning and slaking. High Calcium Dolomitic Chemical Terms Symbol Limestone Limestone Per Cent. Per Cent. Silica SiO 2 1.00 .93 Alumina A1 2 O 3 ) Qft o Q Ferric oxide Fe 2 O 3 J Lime CaO 54.24 32.73 Magnesia MgO .80 19.37 Carbon dioxide ) , T T ... v CO 2 ) ,,0 ft /t KQ 1 .r . > (Loss on Ignition) TT Q f 43 . Uo 4o . 58 All the above ingredients may be classed under three heads; im- purities: silica, alumina and iron oxide; material removed by burning: carbon dioxide and water; and the lime ingredient: lime and magnesia, the only two materials which confer valuable properties on the burned product. It is possible from the above analysis to calculate the composition of the lime which would be produced by burning either of the above stones. The amount of material indicated by loss on ignition is that portion which is driven off, all the other ingredients remaining in the burned product. It follows therefore, that from 100 parts of the above high calcium stone there would remain after burning only 56.94 parts of high calcium lime (10043.06 [loss on ignition] =56.94). The quan- tities of the various ingredients other than those included in loss on ignition are present in the lime; therefore, the percentage composition of the burned lime is calculated as follows: 10006 on Al 2 3 +Fe 2 8 ^T94 = l ' 58% CaO !t4/ = 9. MgO ^ ~= 1.40% 18 The composition of the lime produced from the dolomitic lime- stone is derived in a similar manner: AlA+FesO, = .73% Ca " = 6 These illustrations show that in order to derive the composition of any lime produced from a stone of known analysis it is only necessary to divide the percentage amount of the ingredient by the difference obtained by subtracting the percentage given for the loss on ignition from 100. The calculation of the composition of the hydrates derived from the above limes by slaking is not quite so simple, still nothing is involved more complicated than the rule of three. As has been stated before, lime is the only compound present which combines with water, and this combination takes place according to the equation CaO+H 2 O = Ca (OH) 2 56 +18 = 74 or each 56 parts by weight of lime give 74 parts of hydrate; then the 95.26 parts of lime would give: 56:74 as 95.26:X X = 125.88 100 parts of the high calcium lime would yield on hydrating as follows: SiO 2 No change 1 . 75 parts Al 2 O 3 -hFe 2 O 3 No change 1 . 58 CaO Change to hydrate 125 . 88 MgO No change 1.40 Total 130.61 The percentage composition of this hydrate would be as follows: Al 2 3 +Fe 2 03 = 1.21% Ca(OH) 2 19 In the same manner, the hydrate produced from the dolomitic lime can be calculated. In this lime there is 61.27% of lime and this amount would yield on hydration as follows: 56:74 = 61. 27:X X = 80.96 SiO 2 No change 1 . 74 parts Al 2 O3+Fe 2 O3 No change .73 Ca(OH) 2 Changed to hydrate 80 . 96 MgO No change 36. 26 Total '" The percentage composition of this hydrate would be as follows: A , 2 3+ Fe 2 3 - .61 In the foregoing the attempt has been made to explain clearly and simply the chemical changes which take place in the manufacture and use of lime some knowledge of this subject is necessary for the manu- facturer if the material is to be prepared in a proper manner. The user of lime also should understand the action of burned lime if the material is to be handled to the best advantage. 20 CLASSIFICATION OF LIME CHAPTER III ORIGIN Limestone is the raw material from which lime is manufactured. In general, limestones have been formed by accumulation of remains of sea organisms, such as the foraminifera, corals and mollusks at the bottom of the sea. These limestones sometime show the fossil remains from which they were formed while in other instances all trace of their organic origin has been destroyed. DEFINITION OF The term "limestone" as used in the lime industry LIMESTONE may be defined as a general term referring to that class of rocks containing 80% or over of the carbonates of calcium and magnesium, which, when calcined, give products which slake upon the addition of water. Limestones are generally differentiated geologically, based upon their different origin, texture and composition. Depending upon their physical appearance, the most important varieties are as follows: CLASSES OF Marble Limestone having a coarse or fine crystalline LIMESTONE structure which has been produced by heat and pressure. Chalk A soft friable limestone composed of finely divided shells consisting principally of those of the foraminifera. Oolitic Limestone (Oolite) A limestone made up of small rounded grains so named because of its supposed resemblance to fish-roe. Marl A soft friable material made up of grains of carbonate of lime generally found in lake basins. COMPOSITION OF Depending upon their composition, limestones are LIMESTONE generally distinguished as follows: Argillaceous or clayey limestone, containing con- siderable clay. Arenaceous or silicious limestone, containing considerable silica or sand. Conglomerate Limestone, containing large pebbles of lime-rock. Dolomite, a double carbonate of calcium and magnesium containing when pure 54.35% of calcium carbonate and 45.65% of magnesium carbonate. Magnesian Limestone, containing between 10 and 30% of magnesium carbonate. High Calcium Limestone, a limestone containing not more than 10% of magnesium carbonate. NOTE The preceding defiinitions are taken largely from the paper presented by Irving Warner and the author before the National Lime Manufacturers' Association in 1910. 21 DEFINITION Lime may be defined as the product resulting from the OF LIME calcination of a limestone consisting essentially of the car- bonates of calcium and magnesium, which slakes upon the addition of water. Since all limes are made from limestone, it follows that a classi- fication of lime might be introduced which would indicate the origin of the lime or the kind of stone from which it was made. Following this system, the term "Marble lime'* would indicate that the lime was pro- duced from marble; " Argillaceous lime" one produced from a argill- aceous limestone and the "Silicious lime" one produced from a silicious limestone, etc. Such a classification, however, would have little practical value for the building trades. A more rational classification is therefore based upon the chemical composition of the stone and the form in which the lime is brought into the market. TYPES OF Classification of lime based upon the chemical composition: LIME (a) High Calcium Lime Containing at least 90% of cal- cium oxide. (b) Calcium Lime Containing from 85% to 90% of calcium oxide. (c) Magnesian Lime Containing from 85% to 90% of calcium and magnesium oxides, 10% to 25% being magnesium oxide. (d) High Magnesium Lime Containing not less than 85% of calcium and magnesium oxide, not less than 25% being magnesium oxide. (e) Hydraulic Lime Which contains so large a percentage of lime silicate, aluminate or ferrate as to give the material the property of hardening under water, but which at the same time contains so much free lime that the burned mass will slake upon the addition of water. BUILDING TRADES Classification of lime and lime products based CLASSIFICATION upon the form in which they are supplied the OF LIME trade: (a) Run of Kiln Lime The product as it comes from the kiln, without any sorting or further preparation. (b) Selected Lump Lime A well burned lime which has been freed from core, ashes and cinder by sorting. (c) Ground or Pulverized Lime Lime which has been reduced in size to pass a J^ inch screen. (d) Hydrated Lime A dry flocculent powder resulting from the treat- ment of quicklime with sufficient water to satisfy chemically all the calcium oxide present. The various kinds of lime mentioned under the chemical classifica- tion may be brought into the market in any of the above four forms. For example, hydrated lime may be prepared from a high calcium, calcium, magnesian or high magnesian lime. 22 CLASSIFICATION OF The terms fat and lean are often applied to LIMES AS FAT, lime and refer only to the working qualities of LEAN OR HYDRAULIC the paste and not to the chemical composition. A fat or rich lime is a term employed by the users of lime, to express smooth working qualities and great sand carry- ing capacity. A lean or poor lime is the opposite of a fat lime. Lieut. W. H. Wright in his book on Mortars published in 1845 classified limes as follows: "Lime which is used for building purposes is rarely pure lime, but besides water and carbonic acid imbibed from the atmosphere contains usually some foreign substances. These sub- stances modify the properties of pure lime, and, when combined with it in certain proportions, entirely change its nature. It will therefore be convenient to arrange the limes employed in construction into four different classes, 1st, the fat limes; 2nd, the poor or meager limes; 3rd> the hydraulic limes and 4th, the hydraulic cements. "The fat limes are more than doubled in volume during the process of slaking, which is always attended with much heat. If converted into paste and immersed in water, they w T ill remain of a soft consistency forever * * * . Builders call them fat limes, because the paste, which they form with water, is soft and unctuous to the touch. "The poor or meager limes include all those which, in slaking, do not undergo an increase of volume equal to twice their original bulk, but exhibit, when immersed, the same qualities as the rich limes, * * * "The hydraulic limes possess the property of setting under water, in periods of time varying from one to forty days after immersion, and continue to harden more or less rapidly, according to the hydraulic energy which they respectively possess. They all slake, but with diffi- culty; the stronger kinds exhibiting few or none of the appearances usually seen in fat lime during the slaking process, little or no vapor being formed, and scarcely any heat disengaged; and they undergo an increase of volume, in the inverse ratio of their hydraulic energy. "The hydraulic cements differ from the limes, in not slaking at all after calcination, unless they are previously pulverized; and they then form a paste with water, without any perceptible disengagement of heat, or augmentation of volume. They contain a large amount of the hydraulic base or principle, and set under water in a much shorter time than the limes require to set in air." The classification of lime based upon the chemical composition and the form in which the material is brought into the market is the most concise and clear, and it is recommended that this classification be used. 23 MANUFACTURE OF LIME CHAPTER IV LIME is produced by expelling the carbon dioxide contained in limestone by means of heat. To accomplish this, it is necessary to heat the stone to the temperature of decomposition and further to supply sufficient heat to liberate the gas from the ston take a hoe, and apply it to the slaked lime in the mortar bed just as you hew wood. If it sticks to the hoe in bits, the lime is not yet tempered; and when the iron is drawn out dry and clean, it will show that the lime is weak and thirsty; but when the lime is rich and properly slaked, it will stick to the tool like glue, proving that it is completely tempered." "Vitruvius, translated by Morris Hicky Mo.-gan, Cambridge, Mass., 1914, page 204. 38 The art of preparing lime mortar of the finest quality has survived in Italy to this day. *" So late as 1851 an English architect, when sketch- ing in the Campo Santo at Pisa, found a plasterer busy in lovingly repair- ing portions of its old plaster work, which time and neglect had treated badly, and to whom he applied himself to learn the nature of the lime he used. So soft and free from caustic qualities was it that the painter could work on it in true fresco painting a few days or hours after it was repaired, and the modeler used it like clay. But until the very day the architect was leaving no definite information could he extract. At last, at a farewell dinner, when a bottle of wine had softened the way to the old man's heart, the plasterer exclaimed, 'And now, signor^I will show you my secret!* And immediately rising from the table, the two went off into the back streets of the town, when, taking a key from his pocket, the old man unlocked a door, and the two descended into a large vaulted basement, the remnant of an old palace. There amongst the planks and barrows, the architect dimly saw a row of large vats or barrels. Going to one of them, the old man tapped it with his key; it gave a hollow sound until the key nearly reached the bottom. * There, signor! There is my grandfather! He is nearly done for.' Proceeding to the next, he repeated the action, saying, 'There, signor, there is my father! There is half of him left.' The next barrel was nearly full. 'That's me!' exclaimed he; and at the last barrel he chuckled at finding it more than half full; 'That's for the little ones, signor!' Astonished at this barely understood explanation, the architect learned that it was the custom of the old plasterers, whose trade descended from father to son from many successive generations, to carefully preserve any fine white lime produced by burning fragments of pure statuary, and to each fill a barrel for his successors. This they turned over from time to time, and let it air- slake in the moist air of the vault, and so provide pure old lime for the future by which to preserve and repair the old works they venerated. After inquiries showed that this was a common practice in many an old town, and thus the value of old air-slaked lime, such as had been written about eighteen hundred years before, was preserved as a secret of the trade in Italy, whilst the rest of Europe was advocating the exclusive use of newly burnt and hot slaked lime." NECESSITY FOR If a good, sound, smooth working lime paste is to be HYDRATED LIME made from lump lime, it is absolutely necessary that the lime be slaked some considerable time before using. Compare the method of slaking recommended by Vitruvius and that of the skilled Italian plasterer with the modern method of slaking the lime in the middle of a ring of sand and almost immediately hoeing in *Hodgson, Concrete, Cement, Mortar, Plaster and Stucco, pages 22 to 25. the sand. In the present practice more often than not, the plaster is placed on the wall or the mortar laid between the bricks within a few hours. Such mortar must contain free lime that has not had time or opportunity to slake. This lime later takes up water causing the mortar to be crumbly or the plaster to crack and pop. In spite of improvements in the method of producing lime with better and more economical kilns, the material is brought into the mar- ket in the same manner as it was centuries ago. Further, the method of slaking lime has changed only for the worse, in that our rapid modern practice does not admit of the slow action of slaking lime thoroughly on the operation. The only improvement in the form of the merchantable lime, known to the author, is that of hydrated lime. This will be dealt with in the next chapter. 40 MANUFACTURE OF HYDRATED LIME CHAPTER VI WITHIN recent years a method has been introduced of treating lime with water in a suitable apparatus in which the lime com- bines with sufficient water to satisfy the chemical requirements of the calcium oxide forming a dry, finely divided flour, the so called Hydrated Lime. Hydrated lime can be defined as the dry fiocculent powder resulting from the treatment of quick lime with sufficient water to satisfy the calcium oxide. This material comes into the market in bags or other convenient packages and is ready for use requiring only gauging with water and mixing with sand in much the same manner as cement is used. The fact that lime could be slaked to the form of a dry powder has long been known, and three methods have been used in the past to produce this powder. METHODS OF 1. Lime, in comparatively small pieces about the size DRY SLAKING of an egg, is placed in a basket and immersed in water for a minute or two until hydration has commenced, when it is withdrawn. The wet lime is generally put in heaps or silos in order to conserve the heat and prevent the escape of the vapor. The material swells, cracks and becomes reduced to a dry powder. 2. Lumps of lime are placed in a heap and wetted at intervals so that the mass is equally moistened throughout. The slaking proceeds as in the first instance. 3. Small pieces of lime are exposed to the air for a number of months. The material absorbs both water and carbon dioxide from the atmosphere, falling to a dry powder. The powdered form consists of a hydrated sub-carbonate of lime containing about 10% to 11% of water. These methods of dry slaking lime are crude, and unless the greatest care is exercised, the resulting dry product will contain particles of un- slaked lime. Further, the hydrates produced by these methods gen- erally work short and possess poor sand carrying capacities; in fact, hydrated lime produced by any of the above methods is only suitable for use on the soil, and such hydrate should not be confounded with hydrated lime manufactured by modern methods. 41 MODERN METHODS The modern method of manufacturing hydrated OF HYDRATING lime depends upon the addition of an exact amount of water to a pre-determined exact amount of lime. By no other method is it possible to produce a hydrate which will contain sufficient combined water to satisfy the demands of the calcium oxide present. It is important that all the calcium oxide be in combination with water, otherwise the hydrate will be unsound and unsuitable for many uses. This point will be insisted upon in any specifications that may be drawn for hydrated lime to be used in the building trade. It is vital for each manufacturer to recognize the fact that the formation of hydrated lime involves a chemical change, requiring the presence of definite amounts of lime and water. Since the process is chemical, it requires the same careful supervision as any other chemical process, such as the manufacture of Portland cement. PIERCE PROCESS The first commercial process used for preparing hy- drated lime in this country was the so-called " Pierce " Process. This consisted in slaking the lime to a wet paste, then drying the paste so as to expell all the excess moisture over and above that needed for the chemical requirements, thereby reducing the material to a form that could be ground. If the process was carefully carried out, a good grade of hydrated lime was produced. This method has been abandoned owing to the excessive cost of manufacture. DODGE PROCESS The second method employed was the so-called "Dodge" Process. This process consisted first in grinding the lime so as to pass a 26 mesh sieve, second in treating a weighed amount of the ground lime with sufficient water thoroughly to satisfy the calcium oxide present and produce a dry hydrate, third the dry hydrate was sifted through fine silk cloth. A description of this method is given in the "Engineering News," Vol. 50, Pages 177 to 179, August 27, 1903, by S. Y. Brigham. In this article it is stated that on the average high calcium limes containing 97% of calcium oxide require about 55 pounds of water to 100 pounds of lime, while dolomitic limes require only 36 pounds of water to 100 pounds of lime to produce a good hydrate. From these two pioneer processes have been evolved, during the last fifteen years, the methods described below which are in use at the present time. CLYDE PROCESS A weighed quantity of ground lime is fed from a hopper directly into a large horizontal pan. This pan is so mounted that it can be rotated around its vertical axis, and there are a series of plows arranged to turn over and mix the material in the pan. To the weighed amount of lime a pre-determined quantity of water is 42 added and the whole mass agitated by revolving the pan. When all the water needed chemically, has been taken up, and the excess driven off as steam, the hydrated lime is dumped through an opening in the centre of the pan. It is customary to take the hydrate directly from the pan, and store it in bins in order to age the product. The dry hydrate from the bins is either screened or graded by means of air separation. CLYDE HYDRATOR REANEY PROCESS A weighed amount of the lime is introduced into the upper end of a cylinder, which is slightly inclined from the horizontal. A sufficient amount of water is added, and the material agitated by revolving the cylinder. Inside of the cylinder there are a series of encircling rings, which act as dams to retard the flow of the lime toward the discharge end. The lighter particles of the hydrate rise and pass over the retarding rings while the heavier, unhydrated particles are retained until the hydration is complete. The lower or discharge end of the cylinder is encircled with a tapering screen; the fine hydrated particles pass through this screen, and are removed. The coarser particles which pass over the screen, are eitner thrown away or returned to the feed end of the hydrator for further treatment. KRITZER PROCESS The cracked or ground lime and water are separately fed into the upper of a series of enclosed cylinders (generally 4 or 6) mounted one on top of the other. The amount of lime is controlled by a screw feeding device and the quantity of water is proportioned by a needle valve. The lime and water are propelled throughout the series of cylinders by means of paddles mounted on a shaft extending through each cylinder; these shafts being rotated by gear- ing on the outside. Both materials are thus carried through the whole series of from four to six cylinders, and the product is discharged from 43 KRITZEK HYDRATOR the lower or last cylinder thoroughly hydrated. The machine is also provided with a stack on the upper cylinder, and openings in the lower cylinder, thus a draft is produced through the cylinders in the opposite direction to the travel of the lime. ) LAUMAN PROCESS The cracked lime is fed directly into an inclined stationary cylinder; within this cylinder are paddles carried on a shaft which feed the lime forward by their revolutions. The water is added through a pipe in the upper end of the cylinder. As the material is gradually fed forward it becomes mixed with w^ater and the hydration takes place. The quality of the hydrate is judged by observ- ing the material discharged from the cylinder. These methods are in commercial use today and a good grade of hydrate can be produced by any of the methods provided sufficient care is taken to assure the addition of the correct amount of water and suf- ficient time is allowed to form a sound hydrate. It is the general custom either to screen the hydrate or to pass it through an air separating system in order to remove particles of unhydrated lime, core and other impurities. It is further important that the heat generated by the action of the lime and water, be removed as rapidly as possible in order to keep the tem- perature of hydration below the point at which the lime "burns" in slaking. IMPORTANT FEATURES In any method of hydrating lime an excess of IN HYDRATING water is used over and above that required to combine chemically with the lime. This excess water is driven off as steam by the heat generated in slaking. The quantity of water required is subject to wide variations, since it is de- pendent upon a number of conditions, such as the temperature of the water, lime and the atmosphere. If too little water is used, some particles of lime will not have access to w r ater and these will not slake but will be present in the finished hydrate, causing it to be unsound. Also too little water results in the production of a hydrate which works short, due to its having been "burned" in slaking. Too much water results in a damp or wet hydrate, which is difficult to handle. The addition of the correct amount of water requires the most careful supervision of any of the operations of hydration if a good grade of hydrate is to be produced. This part of the operation must be carefully controlled and be subjected to checks from day to day. PROPERTIES OF HYDRATED LIME CHAPTER VII WATER CONTENT IN HYDRATED LIME Hydrated lime is a fine dry powder consisting essentially of calcium hydrate and magnesium oxide. The amount of combined water contained in the hydrate varies directly as the calcium oxide content. Since cal- cium oxide is the only compound present in lime which possesses the prop- erty of combining with water, it follows that the greater the amount of calcium oxide present in the lime, the greater will be the amount of water required to combine with it. A more complete explanation of this fact has been given in the chapter devoted to the Chemistry of Lime. This is illustrated by the table given below: Percent of calcium oxide Percent of calcium oxide in original lime in hydrate 100 (a) 75.675 95 (b) 72.78 58.34 (c) 49.12 52 (d) 44.55 (a) Pure high calcium lime (b) High calcium lime 5% impurities (c) Pure dolomitic lime (d) Impure dolomitic lime Pure high calcium hydrate contains 24.32% of combined water, while a pure dolomitic hydrate contains only 15.78%. As the amount of impurities (silica and clay) increases, the amount of combined water decreases. This may be seen by comparing (b) with (a) and (d) with (c) in the above table. CHEMICAL COMPOSITION OF The chemical compositions of various com- VARIOUS HYDRATED LIMES mercial hydrated limes are given below: Percent of water required in hydrate 24.325 23.08 15.78 14.33 No. 1* 2* 3* 4* 5** 6* 7* Silica Alumina Iron Oxide Lime Magnesia Carbon Dioxide Water .42 !si 72.25 1.47 .57 24.98 .97 .29 .33 69.63 4.11 1.88 22.56 .95 .50 .51 71.66 .36 1.80 23.81 1.23 .42 .18 71.22 1.88 1.37 23.76 .96 .63 .13 73.45 .58 .69 23.97 3.05 .20 .30 48.76 30.04 .92 16.32 .24 .22 .06 52.27 28.96 16]79 73.72 73.74 72.02 73.10 74.03 78.80 81.23 Combined Oxides ) CaO+MgO (Calculated) f 1 Maine 3 Pennsylvania 5 Washington 7 Ohio 2 New Jersey 4 Alabama 6 Michigan Numbers 1, 2, 3, 4 and 5 represent high calcium hydrate. Numbers 6 and 7 represent dolomitic hydrate. *Analyses from Technologic Paper No. 16, Manufacture of Lime, Bureau of Standards. ** Analysis by Author. 46 PHYSICAL AND CHEMICAL In 1909 the author gave a table showing the CHARACTERISTICS most important chemical and physical char- acteristics of hydrated lime to the National Lime Manufacturers' Association. This table is here reproduced. DOLOMITIC HYDRATES HIGH CALCIUM HYDRATES 1 Weight per cu. ft. loose 2 Weight per cu. ft. shaken 3 Specific Gravity 4 Residue Insoluble in hydro- chloric acid 5 Moisture 6 Combined water 7 Carbon Dioxide 8 Available Oxide 30.40 31.72 37.20 36.30 36.40 36.23 42.40 45.10 2.50 2.53 2.41 2.50 .40% .40% .24% .28% .30 .00 .35 .00 17.22 15.88 18.07 17.29 .75 .30 .41 .17 80.38 83.02 80.47 82.03 35.70 35.80 41.20 45.30 2.16 2.07 .25% .33% .00 .00 24.52 24.37 .54 .15 74.00 74.96 Referring to the table, the horizontal line 1 gives the weight per cubic foot, loose. Line No. 2 gives the weight per cubic foot, shaken. Line No. 3 gives the specific gravity this is obtained by dividing the weight of the substance by the weight of the same volume of water. It is, therefore, a measure of density, and gives the relative weight of the unit volume of the material as compared to the weight of unit volume of water. The higher specific gravity of the dolomitic hydrate is due to the fact that only the lime present in the calcined dolomite combines with water, the magnesia being present as the oxide. From the specific gravity and the weight per cubic foot of any material it is possible to calculate the amount of voids or the space occupied by the air. Assume the specific gravity of a hydrate to be 2.50 and the weight to be 40 Ibs. to the cubic foot. The specific gravity means that a cubic foot of perfectly solid hydrate weighs 2.50 times as much as a cubic foot of water. A cubic foot of water weighs 62.4 Ibs., then a cubic foot of hydrate (perfectly solid containing no voids) would weigh 62.4 X 2.50 = 156 Ibs. The hydrate, however, weighed only 40 Ibs. per cubic foot, therefore the air occupied a space equal to such a volume of hydrate as would weigh (156-40 = 116) 116 Ibs. The per cent of voids would be 116/156 = 74.4%. Line No.4 is the residue insoluble in dilute hydrochloric acid (muriatic acid) and consists of sand, clay, or ashes present in the hydrated lime. In every case (except in hydraulic hydrates) this is inert material and has no value as a binding agent; it should, therefore, be looked upon as an impurity and in case the amount is over 2% it would materially injure the sand carrying capacity of the hydrate. 47 Line No. 5 gives the amount of water present as free (or mechanically contained) moisture and not combined with the lime. This should be present only in small quantities. If too great an excess of water is present the hydrate will have a tendency to lump or cake. Line No. 6 gives the amount of water which has entered into chem- ical combination with the lime to form the hydrate and which is a neces- sary and important ingredient. The amount should always be sufficient to satisfy all the calcium oxide present. Attention has been called to the fact that the amount of combined water is always greater in the high calcium hydrates. Line No. 7 gives the carbon dioxide (carbonic acid gas) present in the hydrate. This gas is in combination with the lime and denotes either the presence of unburned limestone (core) or that the hydrate has taken up carbonic acid from the atmosphere; in any case the amount present should be small, less than 2%, otherwise it indicates an inferior hydrate. The lime already combined with carbonic acid is inert and unable to contribute any strength to the mortar. Line No. 8 : in this horizontal line the amount of caustic oxides present has been calculated, that is, the amount of bonding material which is capable of uniting with the carbonic acid of the atmosphere thereby producing the bond of the mortar. This is deduced by subtracting from 100 the residue insoluble in hydrochloric acid (4), moisture (5), combined water (6) and the amount of calcium carbonate corresponding to the C(7)X100 ) amount of carbonic acid present in the hydrate < - The numbers in parenthesis refer to the horizontal lines in the preceding table. 48 USE OF HYDRATED LIME IN SAND MORTARS CHAPTER VIII IT may be stated that hydrated lime is suitable for any use in the building trade to which lump lime can be put. This in general includes its use in mortars and plasters aH44lrWouId appearthttt-fts thejnaterial^becQmes better known, its advantages will be found to outweigh any disadvantages. A i^tftar made with hydrated lime often does not trowel quite so easily as a mortar made from lime putty. The smooth working qualities of the hydrate can be greatly improved by proper method of manufac- turing and by allowing the mortar or paste to soak over night so that the gauging water becomes thoroughly incorporated. The great ease of handling hydrate and the thoroughness with which it has been slaked make up to a great extent for any lack of plasticity. The use of hydrated lime does away with the necessity of slaking lime to a paste, thus saving the cost of slaking. It is estimated that it costs 25 cents a barrel to slake lime in a mortar box. Hydrated lime comes into the market in convenient packages of a definite weight. This makes it possible to proportion the mortar so as to have exact quantities of lime and sand present, a fact which is always appreciated both by the archi- tect and engineer. It is much more difficult to obtain accurate propor- tions of lime and sand when lump lime is used, especially as it is a general custom to add as much sand as possible with the result that the mortar is often over-sanded and possesses little strength. ADVANTAGES OF In June, 1910, the author presented the results HYDRATED LIME obtained from an extended series of tests on mortars made from both hydrated and lump lime, to the American Society for Testing Materials.* One of the most important conclusions drawn from these investigations was that the mortar produced from hydrated lime was stronger than that produced from the correspond- ing lump lime slaked to a paste. This conclusion was to be expected, since it is possible to manufacture hydrated lime by mechanical means under good chemical control, which is more thoroughly slaked than it is possible to slake lump lime on the job. The user in dealing with hydrated lime is handling a product which can be definitely proportioned and will *Proceedings American Society for Testing Materials, 1910. 49 produce known results. The quality of hydrate desired can be specified in advance and the material can be inspected and tested (see specifica- tion for hydrate, page 84) in order to determine if it fulfills the require- ments. The quality of quicklime can also be specified and its character determined by tests, but such tests do not indicate what will be the quality of mortar found on the job, since lime is chemically changed during slaking. Hydrated lime undergoes no further change upon the addition of water, therefore the same material is tested which is to be used. The testing of hydrated lime is no more difficult than the testing of cement. With lump lime the user is dependent always upon the thoroughness of slaking and it is well known that unless the paste is run off and stored for some considerable time, there is no assurance of complete and thorough slaking. Practically all those who investigated the strength of lime mortars have recommended the use of hydrated lime rather than lump lime. In Circular No. 30, 1911 of theBureau of Standards, the following statement is made: "The proportion of impurities in hydrated lime is generally less than that in the lime from which it is made. In building operations hydrated lime may be used for any purpose in place of lump lime, with precisely similar results. The consumer must pay the freight on a large amount of water, but the time and labor required for the slaking is eliminated and there is no danger of spoiling it either by burning or in- complete slaking * * *. For all building purposes hydrated lime is to be preferred to lump lime. By its use the time and labor involved in slaking may be saved and the experience of the laborer is eliminated as a factor in the problem." From the above it will be seen that those who have carefully investigated hydrated lime are firm in their opinion that it is safer and superior to lump lime. In the past when lump lime was used almost exclusively for plaster- ing, it was the practice to slake the lime and allow it to season for some considerable time before using in order that the plaster should contain no particles of quicklime. This occasionally caused delay in the con- struction of buildings. Moreover, plaster made from lime does not set quite so rapidly or in the same manner as gypsum plaster. These two points have led people to believe that buildings plastered with hydrated lime are delayed in the course of construction. By the use of hydrated lime the delay due to slaking and seasoning is done away with, and by a proper method of planning and rotating the work, the job can be com- pleted without delay. 50 SECOND NATIONAL BANK BUILDING, TOLEDO, OHIO D. H. BURNHAM Co., CHICAGO, ILL., ARCHITECTS Hydrated Lime Plaster Used Throughout for Scratch, Brown and Finish Coats SELECTION In the preparation of mortar or plaster, generally little atten- OF SAND tion is paid to the quality of the sand employed. Since the sand forms three-quarters or more of the mortar, it follows that the strength is largely dependent upon the quality of the sand used. Sand for use in lime mortars should be clean, free from dirt and loam, and as coarse as is consistent with the character of surface desired. Investigations of sands have shown that coarse sand yields a stronger mortar than fine sand. It is better to use as coarse sand as possible if a strong mortar is desired. This is particularly the case in mortars used in brick work where the joints between the bricks are wide. The grada- tion of the sand grains, that is, the amount of the different sized grains present, should be such as to give the greatest density or the least voids in the sand. The following specifications for a mortar sand are taken from Bulletin No. 70, University of Illinois: "The sand shall consist of grains of hard, tough, durable rock and must be free from soft, decayed or friable material. "The suspended matter shall not exceed 6% by weight. "Not more than 15% by weight, including the suspended matter, shall pass a No. 100 screen nor more than 80% a No. 16 screen. "The voids shall not exceed 35% of the total volume." SAND-CARRYING The statement is often made that hydrated lime will CAPACITY OF not carry so much sand as lime paste. This is really HYDRATED LIME not the case. It is not to be expected that 200 pounds of hydrated lime will carry as much sand as 200 pounds of lump lime slaked to a paste for the simple reason that 200 pounds of hydrate contains less calcium and magnesium oxides than the paste resulting from slaking 200 pounds of lump lime. By referring to the equation for slaking lime on page 15, it will be seen that 56 pounds of pure high calcium lime gave 74 pounds of hydrate; therefore, 200 pounds of lime would give (56:74 = 200 :X) 264 pounds of dry hydrate. Thus 264 pounds of hydrated lime contains the same amount of calcium and magnesium oxide as 200 pounds of lump lime slaked to a paste. It would require 264 pounds of hydrate to carry the same amount of sand as 200 pounds of lump lime. MACHINE MIXED Within the last few years machines have been placed MORTAR on the market to mix the sand and lime, these machines being similar in operation to a concrete mixer. By the use of such machines, it is possible to mix the lime and sand more thoroughly and the mixing is accomplished in less time than is required by hand. Hydrated lime is especially adapted for use in the mortar mixer because the material comes on the work in a convenient form and in packages of known weight. 52 On a recent job with which the author is familiar, all the mortar used in the brick work was mixed in this manner. The mixing machine was operated only during the last few hours in the afternoon, enough mortar being prepared for next day's requirements. The mortar mixed in the machine was dumped into the basement in a pile and was allowed to age over night. When used the mortar was entirely satisfactory and worked free and smooth. PROPORTIONS OF Below are indicated the approximate proportions of MATERIALS hydrate and sand to be employed in mortar for various uses. It is not possible to give specifications covering all conditions, since different hydrates will carry varying quantities of sand and more particularly because the character of the sand materially influences the quantity of hydrate required. PROPORTIONS FOR HYDRATED LIME PLASTER* WOOD LATH THREE COAT WORK The following are the proportions in which materials should be mixed at the mixing plant or by the contractor on the job: PER TON OF PER HUNDRED POUNDS OF SANDED PLASTER HYDRATED LIME SCRATCH COAT 1550 pounds sand 350 pounds sand 450 pounds hydrated lime 100 pounds hydrated lime 3J/2 pounds hair % pound hair BROWN COAT 1600 pounds sand 400 pounds sand 400 pounds hydrated lime 100 pounds hydrated lime 13/2 pounds hair % pound hair FINISH COAT, WHITE Lime putty properly gauged with Plaster of Paris SAND FLOAT FINISH 1450 pounds sand 275 pounds sand 550 pounds hydrated lime 100 pounds hydrated lime *These are average mixtures for first class, clean, sharp plastering sand. Mixtures may be changed to meet other qualities of sand. 53 WOOD LATH TWO COAT WORK PER TON OF PER HUNDRED POUNDS OF SANDED PLASTER HYDRATED LIME FIRST COAT 1550 pounds sand 350 pounds sand 450 pounds hydrated lime 100 pounds hydrated lime 3j^ pounds hair % pound hair FINISH COAT, WHITE Lime putty properly gauged with Plaster of Paris SAND FLOAT FINISH 1450 pounds sand 275 pounds sand 550 pounds hydrated lime 100 pounds hydrated lime METAL LATH THREE COAT WORK PER TON OF PER HUNDRED POUNDS OF SANDED PLASTER HYDRATED LIME SCRATCH COAT 1550 pounds sand 350 pounds sand 450 pounds hydrated lime 100 pounds hydrated lime 4 pounds hair 1 pound hair BROWN COAT 1600 pounds sand 400 pounds sand 400 pounds hydrated lime 100 pounds hydrated lime l*/2 pounds hair Yi pound hair FINISH COAT, WHITE Lime putty properly gauged with Plaster of Paris SAND FLOAT FINISH 1450 pounds sand 275 pounds sand 550 pounds hydrated lime 100 pounds hydrated lime BRICK OR TILE THREE COAT WORK PER TON OF PER HUNDRED POUNDS OF SANDED PLASTER HYDRATED LIME SCRATCH COAT 1600 pounds sand 400 pounds sand 400 pounds hydrated lime 100 pounds hydrated lime \Yl pounds hair % pound hair BROWN COAT 1600 pounds sand 400 pounds sand 400 pounds hydrated lime 100 pounds hydrated lime FINISH COAT, WHITE Lime putty properly gauged with Plaster of Paris SAND FLOAT FINISH 1450 pounds sand 275 pounds sand 550 pounds hydrated lime 100 pounds hydrated lime 54 BRICK or TILE TWO COAT WORK PER TON OF PER HUNDRED POUNDS OF SANDED PLASTER HYDRATED LIME FIRST COAT 1600 pounds sand 400 pounds sand 400 pounds hydrated lime 100 pounds hydrated lime 1^2 pounds hair Y% pound hair FINISH COAT, WHITE Lime putty properly gauged with Plaster of Paris SAND FLOAT FINISH 1450 pounds sand 275 pounds sand 550 pounds hydrated lime 100 pounds hydrated lime ON CONCRETE 100 pounds sand 800 pounds hydrated lime 250 pounds calcined plaster WOOD LATH, BRICK OR TILE ONE COAT W'ORK 1550 pounds sand 450 pounds hydrated lime 3J/2 pounds hair GYPSUM BLOCK THREE COAT WORK Use the same quantities as shown for Brick or Tile. NOTE Mixtures specified on pages 53, 54 and 55 are average mixtures for first class, clean, sharp plastering sand. Mixtures may be changed to meet other qualities of sand. HAND MIXED In preparing these mortars, the best and most economical MORTARS results will be obtained by the use of a mortar mixing machine, several of which are on the market. If hand mixing is to be used, two methods may be employed in preparing the mortar. FIRST Soak the hydrate with water so as to produce a thick paste, and allow to stand over night, then add the desired amount of sand and sufficient water to give the required consistency to the mortar. It is generally conceded that this method produces the more plastic mortar. SECOND Mix the hydrate and sand dry, the same as with cement mortar, then add the water to produce the required consistency. 55 When hair is used, it should always be well soaked and beaten before mixing with the mortar. Thorough hoeing and mixing always improves the plasticity and working qualities of a mortar. LIME-CEMENT MORTARS In many cases where a mortar having a greater strength is required, or it is advisable to have considerable strength produced quickly, it is advantageous to use Portland cement in the mixture. Investigations by various authorities have proven the fact that hydrated lime and Portland cement can be mixed in any proportions from an addition of 10% of hydrate to the Portland cement for making a cement mortar to an addittion of 10% of Portland cement to the hydrate for making a hydrated lime mortar. The addition of hydrated lime to a cement mortar improves the plasticity and water tightness, and the addition of Portland cement to a hydrated lime mortar increases the early time strength. STRENGTH OF From the results obtained by many investigations it CEMENT-LIME may be stated that the replacement of 25% of Portland MORTARS cement with hydrate in mortar does not materially weaken the mortar. Mr. Emley* from his investiga- tion drew the following conclusion : "1. While the strength does decrease with increasing proportions of lime, samples containing 25% lime are not very much weaker than those made of cement. 2. High calcium lime sets more rapidly than dolomitic lime. Specimens containing the former are therefore stronger when 7 days old. Those containing dolomite were almost as strong at 28 days and at 3 months had just about caught up to the high calcium limes. 3. Samples stored under water set more slowly than those stored in air, and were therefore weaker at 7 days. But at 3 months those stored under water were much the stronger, frequently showing twice the strength of the specimens stored in air. This applies equally to all specimens containing 25% or less of lime, whether dolomitic or high calcium." Following will be found the results obtained from an extended series of tests made under the direction of Prof. Ira H. Woolson of Columbia University, N. Y.** The charts on pages 57 to 60 clearly illustrate the greater strength developed by mortars made with hydrated lime over those made from the corresponding quick lime slaked to a paste. The curves plotted were obtained by averaging the results on similar tests of three different hydrated limes and three different quick limes. *The use of hydrated lime in a Portland cement mortar, by Warren E. Emley and H. P. Greenwald, Proceedings, National Lime Manufacturers Association, 1913. """Comparative Test of Lime Mortar, both in tension and compression, by E. W. Lazell, Proceedings of American Society for Testing Materials, Page 328, 1910. 56 Tension Tests Average, 1 to 3 Mixture. r .85 Cement, ^i f .50 Cement t ,15 Lime, J 1 .50 Lime, 3 Sand. 3 Sand. 1 Lime, 3 Sand. Quick- Hy- Quick- Hy- Quick- Hy- lime. drate. lime. drate. lime. drate. 28 days 288 365 103 176 37 83 3 months.... 352 399.5 127 225 43 99 12 months 502 517 174 267 81 125 Percentage of Hydrated Lime is by weight of Portland cement 57 Compression Tests Average, 1 to 3 Mixture. ( .85 Cement, ) 1 .15 Lime, j J .50 Cement, \ t .50 Lime, j 1 Lime, 3 Sand. 3 Sand. 3 Sand. - Quick- Hy- Quick- Hy- Quick- Hy- lime. drate. lime. drate. lime. drate. 28 davs . 1,999 2,170 704 858 230 210 a "* j months . . . . 2,451 2,810 859 1,132 199 677 12 months. . . . 4,001 4,263 1,837 2,116 273 840 Percentage of Hydrated Lime is by weight of Portland cement 58 Tension Tests Average, 1 to 5 Mixture. 65 Cement. .35 Lime. 1 Lime, 5 Sand. 5 Sand. Quicklime. Hydrate. Quicklime. Hydrate. 28 days . 99 214 33 36 3 months ... 112 316 48 60 12 months . 160 277 67 93 Percentage of Hydrated Lime is by weight^of^Portland cement 59 COMPRESSION SQO 7SC ZB-D J-M< 28 days 3 months. . 12 months. . Compression Tests Average, 1 to 5 Mixtures. .65 Cement, .35 Lime. 1 Lime, 5 Sand. 5 Sand. Quicklime. Hydrate. Quicklime. Hydrate. . " 574 1,339 126 175 642 1,801' 150 316 1,422 3,338 343 565 Percentage of Hydrated Lime is by weight of Portland cement 60 EQUITABLE BUILDING, NEW YORK CITY R. E. GRAHAM, CHICAGO, ARCHITECT Hydrated Lime Used Throughout in All Brick Mortar It is often stated that lime made from dolomite is unsuitable for use in connection with Portland cement because of the high magnesia content. This is not the fact as is shown by the results given in the charts, since these cover tests made on both high calcium and dolomitic limes. It may be stated that the magnesia contained in dolomitic limes shows no deleterious action but on the contrary is a valuable ingredient and con- tributes to the strength of the mortars. Proportions for hydrated lime-cement mortar, proportions being given by weight: BRICK MORTAR THREE TO ONE MIXTURE Four bags Portland cement, one bag (100 Ibs.) hydrated lime* and 1,500 pounds sand. FOUR TO ONE MIXTURE Three bags Portland cement, one bag (100 Ibs.) hydrated lime* and 1,600 pounds sand. FIVE TO ONE MIXTURE Two bags Portland cement, one bag (100 Ibs.) hydrated lime* and 1,500 pounds sand. STAINLESS CEMENT MORTAR 300 pounds white cement, 100 pounds hydrated lime and 1,200 pounds sand. FOR TILE SETTING OR ROOFING TILE 85% of Portland cement, 15% of hydrated lime used with 3 parts sand. CEMENT-HYDRATED LIME MORTAR FOR INTERIOR PLASTERING ON- BRICK OR TERRA COTTA: SCRATCH COAT (OR FIRST COAT) One bag Portland cement, 2 bags (200 Ibs.) hydrated lime and 1,200 pounds sand. BROWN COAT (OR SECOND COAT) One bag Portland cement, 2 bags (200 Ibs.) hydrated lime and 1,200 pounds sand. CEMENT MORTARS FOR FIREPROOFING PARTITIONS 100 pounds hydrated lime to 400 pounds Portland cement, and 1,500 pounds sand. *Hydrated lime is usually sold in 100 ll>. burlap or cotton sacks and 40 or 50 Ib. paper sacks. USE OF HYDRATED LIME IN CONCRETE CHAPTER IX PLASTICITY OF During the time of mixing and placing concrete and HYDRATED LIME up to the time of beginning of the hardening, concrete may be considered as a plastic material. The term plastic as used in reference to concrete and mortar may be denned as that property which allows the material to be cast or moulded into shape. The plastics differ from most materials of construction in that their strength and structural integrity depend to a much greater extent on the skill of the user than upon that of the manufacturer. For example, the quality of concrete is much more dependent on the quality of stone, sand and workmanship than on the quality of Portland cement. In a treatise of this kind it is impossible to discuss in detail how the hardening of the cement is affected by the character of the sand and stone and the method of mixing and placing. It will be readily recognized that the quality of the concrete is largely dependent upon its plasticity or the ease with which the plastic mass of stone, sand, water and cement will flow into place and assume its final form. This being the case, anything which will improve the plastic quality of the wet mass without materially decreasing its strength after hardening will be found advantageous. VALUE IN MORTARS The value of concrete and mortars in construction AND CONCRETE work depends upon the ease of manipulating them in a plastic state supplemented by the quality of subsequent hardening to a stone-like mass. It is possible to increase the plasticity by using an excess of water, and this is commonly done. Two defects are introduced by the use of too much water. 1st. There is great danger of a separation between the stone and mortar (sand and cement) if the mixture is too wet, resulting in weak stratified concrete. 2nd. The excess water over and above that required by the cement must be expelled in part by gravity and in part by evaporation. Since the original water occupies space, it follows that its removal results in voids and a non-dense concrete. In large slabs the loss of the water may cause shrinkage and cracks. The addition of a large amount of excess water, w r hile it makes the cement mass easier to pour, always results in a lack of density, thereby producing a weak concrete. 63 "1 "ll SB a s 89 sill IS II as a L LEADER-NEWS BUILDING, CLEVELAND, OHIO CHAS. A. PLATT, ARCHITECT Hydrated Lime Used in All Concrete and Brick Mortar INCREASED It is well known that the addition of a small amount of PLASTICITY hydrated lime (10% or more by weight, of the Portland OF CONCRETE cement used) renders the concrete mass much more plastic and that less water is required to make the mass work- able. As the results of experiments and practical observation, it has been proven that the small amount of hydrate improves greatly the ease of handling the concrete and that it further results in a denser concrete. The greatest advantage of the use of hydrate is this quality of rendering the concrete mass more plastic. Because of this increased plasticity the same amount of tamping results in a denser concrete. An illustration of the increase in plasticity of concrete, due to the addition of hydrated lime, recently came to the author's observation. In the construction of a large dam in the Northwest, the quarry and rock- crushing plant were located on a hillside, about 400 feet above the river. Since no good sand was available, the fine part of the aggregate was manufactured from the rock. The concrete mixing plant was also located on the hill, above the crest of the dam, and practically all the concrete was spouted into place through chutes about 285 feet long, which had an inclination of 18. In this manner about 30,000 cu. yds. of concrete was placed. The concrete used was a 1:3:5 mix, using cement, sand and stone, with an addition of 10% hydrated lime. Without the addition of the hydrate, the wet concrete would not flow in chutes, but would dam up and then spill over the side. With the addition of hydrate, the material flowed smoothly and there was very little separation of the mortar from the stone. Throughout the construction of the whole dam, test cylinders were made, 6" in diameter X 12" long, and these were broken at regular intervals. These cylinders were made at the site of the dam from the material being deposited. The result showed a con- siderable improvement both in the quality and the strength of the con- crete, due to the hydrated lime. RETENTION OF SUFFICIENT It is a well known fact that lime paste tends MOISTURE TO PREVENT to retain the water mechanically mixed SHRINKAGE CRACKS IN with it. This quality of hydrated lime is CONCRETE - particularly valuable when the concrete is spread out in a thin sheet with one surface exposed to the air, as is the case in concrete floors, sidewalks and roads. Practical experience has shown that the more rapidly the mass dries, the greater the likelihood of cracking. This cracking has been attributed to the fact that the rate of surface evaporation is greater than the flow of water from the interior to the surface, causing unequal drying, a condi- tion which gives rise to strain and more or less marked ruptures. During 66 CONCRETE ROAD, GARRET Co., MARYLAND 10% Addition of Hydrated Lime to 1-2-4 Concrete (Monolithic Type) the early period of drying out and until the concrete has set and hardened, it has little or no strength, and its cohesion is negligible. In this condi- tion it is evident that the slightest shrinkage must result in the formation of cracks. Even though the cracks be so small as to be scarcely notice- able, they are a source of weakness when the hardened concrete is subject to tensile strains. The prevention of the formation of shrinkage cracks is not so important in mass concrete subject only to compression or in reinforced concrete where the tension is provided for by the steel rein- forcement, but when used in a thin slab as is the case in concrete roads and pavements, it is very important to reduce the cracks due to shrinkage to a minimum. The addition of a small amount of hydrate to the concrete mass reduces the formation of shrinkage cracks by rendering the mass denser and thereby retarding the evaporation. Further, by rendering the mass more plastic, it prevents the separation of the mortar from the stone, thus producing a more uniform mass. In some recent road work in which 10% of hydrated lime was used throughout the concrete, it was found that fewer cracks developed in this road than in sections having the same composition but in which no hydrate was used. 1 1 ** BHB METHODS OF Concrete can be rendered water-tight in a number WATERPROOFING of ways: CONCRETE 1. By carefully grading and proportioning the aggre- gate and the cement. 2. By the application of layers of materials impervious to water, such as asphalts, bitumen, etc., with or without cloth or felt. 3. By plastering the outside surface of the concrete with a rich Portland cement mortar. 4. By the introduction of some foreign material or materials into the mixture. Ignoring the methods mentioned under Nos. 2 and 3, which both depend for their water-proofing quality upon a layer of material impervi- ous to water, thus keeping the water away from the concrete itself, but which do not render the concrete mass impervious to water, we will deal only with Nos. 1 and 4. The greatest objection to the use of imper- vious materials such as asphalt, bitumen, etc., either with or without felt or cloth, is the durability of the materials themselves. In a few years, most, if not all, of these substances oxidize, disintegrate and become porous. Method No. 1 depends on selecting materials which are so graded that they give the densest possible concrete. This method is fully described in Taylor and Thompson's book on "Concrete, Plain and Reinforced." The method requires a careful selection of the sand and stone, careful proportioning of the same, and extreme care in mixing and placing. NECESSARY QUALIFICATIONS It would be a great advantage to engineers FOR WATERPROOFING if some method of rendering concrete more MATERIAL - impervious to water were known. Thus, if some ingredient could be added to the con- crete mass to produce this, the advantage would be apparent. Such an ingredient should possess the following characteristics: 1. It should be easily mixed with the materials forming the con- crete aggregate. 2. It should not in any way injure the character of the concrete or have a deleterious action on the cement. 3. It should be preferably of a character chemically similar to that of the cement. 4. It should not be subject to alteration, decomposition or decay, and should be a mineral compound rather than organic. 70 5. The material should be bulky and preferably of a colloidial nature, so as to fill the interstices of the concrete mass. 6. It should not be so expensive as to make the cost of the con- crete excessive. 7. It should be easily procurable and handled. In looking over these requirements, it will be seen that such materials as oils, waxes and other organic bodies do not fulfill the specifications. They are not of a character similar to the cement, are not easily mixed with the concrete aggregate, and, as they are organic, are subject to alteration and decay. Most of the so-called water-proof compounds on the market at the present time which are to be incorporated in the con- crete mass itself contain organic bodies, such as the lime salts of fatty acids, oils, paraffin or Japanese wax, either alone or in combination with other ingredients. While the action of these bodies is to render the con- crete mass in the early stages less impervious to water, it is doubtful how long this beneficial action will continue. In a report of the committee on water-proofing rendered to the American Society for Testing Materials and published in the Proceed- ings for 1907, the following statement is made: "The only conclusion possible at the time, from data so far obtained, indicates that the majority of waterproofing compounds examined under the j urisdiction of sub-committee A, are no more effective than untreated properly proportioned mixtures which certainly can be made absolutely w^ater-proof by the use of proper materials and well proportioned mix- tures." Experiments made under the author's direction confirm these con- clusions as applying to water-proof compounds which contain organic materials. HYDRATED LIME AS Referring again to the specifications, it will be seen A WATERPROOFING that a material to meet the requirements fully MATERIAL should have a mineral base and should be composed chiefly of lime so as to be similar to cement in its chemical characteristics. It would, therefore, seem that hydrated lime would be a material which would most nearly fill the requirements. Clay has been suggested as a suitable material, but its use in practice would be impracticable owing to the tendency of its particles to adhere, forming balls; these balls have little adhesion, and hence injure the strength of concrete. 71 RESERVOIR AT WALTHAM, MASSACHUSETTS FlVE PER CENT. OF HYDRATED LlME ADDED BY WEIGHT OP CEMENT The following results of tests are given to illustrate the water- proofing properties of hydrated lime: TENSILE STRENGTH LBS. PER SQUARE INCH* 1-3 Tests Water Exposure Age of Test Piece .95 P. C. .05 L. 3 Sand .90 P. C. .10 L. 3 Sand .85 P. C. .15 L. 3 Sand .80 P. C. .20 L. 3 Sand .75 P. C. .25 L. 3 Sand .70 P. C. .30 L. 3 Sand 7 days 28 days 3 months 6 months 9 months 12 months 157 311 389 321 301 336 189 364 419 341 308 311 239 264 372 278 279 322 237 268 374 260 268 299 173 259 314 207 250 260 173 268 281 253 232 231 NOTE P. C., Portland Cement; L., Hydrated Lime. Percentage of Hydrated Lime is by weight of Portland cement These results indicate that quite large additions of hydrated lime can be made to cement mortars even when they are exposed to the action of water. The hydrated lime in this instance acts as a filling material, and as it is of a colloidial nature should render the mortar more imper- vious to water. In order to investigate this water-tight character of mortar, circular pats were made of the different mixtures 3" in diameter and 1" thick. *Lazell Proceedings American Society for Testing Materials, 1908. 72 These were then placed in an apparatus in such a manner that the water could act upon them in the centre through an opening exactly 2" in diameter. Thus the area acted upon is 3.1416 square inches. All pats were subjected to a pressure of thirty pounds for one hour. PERMEABILITY TESTS 1-3 MIXTURES* Composition of Test Piece Amount of water passing through test piece in one hour under 30 Ib. head, in cubic centimeters Age of Test Piece 7 days 28 days Remarks IP. C. 3 Sand 10 cc .95 P. C. .05 Hydrate 3 Sand 5cc Equivalent to replacing 5% of the cement by Hydrate .90 P. C. .10 Hydrate 3 Sand 2cc Equivalent to replacing 10% of the cement by Hydrate .85 P. C. . 15 Hydrate 3 Sand 0.3cc Equivalent to replacing 15% of the cement by Hydrate NOTE P. c Portland Cement. Percentage of lime is in terms of weight of cement. PERMEABILITY TESTS. 1-5 MIXTURES 28 days 6 Weeks Remarks IP. C. 5 Sand 3000 cc 1090 cc .95 P. C. .05 Hydrate 5 Sand Equivalent to replacing 5 cc 3 cc 5% of the cement by Hydrate .90 P. C. . 10 Hydrate 5 Sand Equivalent to replacing 2 . 5 cc 10% of the cement by Hydrate .85 P. C. . 15 Hydrate 5 Sand Equivalent to replacing 15% of the cement by Hydrate NOTE P. C., Portland Cement. Percentage of lime is in terms of weight of cement. *E. W. Lazell Proceedings American Society for Testing Materials, 1908. 73 Referring to the preceding tests it will be seen that the addition of even small amounts of hydrated lime to mortar materially increases its water-tightness. Sanford E. Thompson,* in an address delivered before the American Society for Testing Materials, in June, 1908, gave tests upon the concrete used for the Waltham, Mass., reservoir as follows: "A few permeability tests with hydrated lime admixtures made by the writer in 1903 indicated it to be a valuable material for water-proof- ing. Later in 1906 when the reservoir at Waltham, Mass.,** which is 100 feet in diameter and 43 feet high, was under consideration, the writer was consulted by Bertram Brewer, City Engineer, in the framing of the specifications and made another series of tests as follows: Permeability Test of 1:2:4 Concrete for Waltham, Mass., Reservoir, 1906 Concrete 4 in. thick. Pressure 80 Ibs. per sq. in. Percentage of Hydrated Lime Flow in Grams per minute At 14 days At 21 days At 28 days 0% A 5.52 9.20 2.82 2.92 2.55 1.49 1.91 1.63 0.76 Percentage of lime is in terms of weight of cement. "This flow is much greater than in the tests described at Cambridge, but the pressure in the Cambridge tests is about one- third higher, the age is greater, and probably, most important of all, the thickness of concrete is twice as great. "As a result of those tests for Waltham, 5% of hydrated lime was adopted for the reservoir to mix with the 1 :2 :4 concrete in building its walls. The results were satisfactory, the only seepage occurring at joints formed between different day's work, where the bond between the old and the new concrete was not made with sufficient care.'* fin a recent address by Sanford E. Thompson, given before the American Society for Testing Materials, in June, 1908, he discussed a series of tests made on concrete composed of Portland cement, sand and stone in varying proportions to which had been added varying amounts of hydrated lime. In making these tests, concrete cubes were used con- taining an embedded pipe through which the water pressure could be applied. The results are given in the table on following page: *Engineering Record June 27, 1908. **Engineering Record January 12, 1907, Page 32. tEngineering Record June 27, 1908. 74 Flow of water under 7-ft. head Flow under pressure of 60 Ibs. per sq. in. Pressure Per cent. Duration Flow applied Duration Flow Mark Hydrat- ed Lime Age of meas- ured flow Grams Hour Age before measure of meas- ured flow Grams per Hour Days Hours Days Hours Hours 1:2:4 concrete No.l 1% 18 161 2.7 40 24 4M 74.8 No. 2 4% 18 161 1.2 41 18 5 28.4 No. 3 7% 18 161 1.0 42 18 G% 5.2 No. 4 10% 15 161 1.0 46 6 18 1.6 1:2^:4^ con. No. 5 0% 30 169 0.3 44 17 6 1.1 No. 6 o% 30 169 1.9 45 18 6 32.5 No. 7 10% 29 169 0.8 49 11 No. 8 14% 29 169 0.7 50 27 1:3:5 concrete No. 9 o% 26 169 9.8 50 6 14 70.6 No. 10 8% 26 169 1.1 51 8 17 3.6 No. 11 14% 28 169 1.1 50 28 13 10.7 No. 12 20% 28 169 1.2 53 9 15 0.7 "The percentages of hydrated lime are based on the weight of the cement, these being added to the cement and not replacing it. The variations in the ages of the specimens in different proportions slightly affects the results and accounts in part for the fact that the 1 :3 :5 mix- tures in the pressure tests are nearly as water-tight as the richer propor- tions. Specimen No. 5, which shows practically no flow, is evidently erratic." He concludes from these experiments as follows: " (1) Hydrated lime increases the water- tight ness of concrete. "(2) Effective proportions of hydrated lime for water-tight con- crete are as follows: "For one part Portland cement: 2 parts sand: 4 parts stone, add 8 per cent hydrated lime. "For 1 part Portland cement: 2J/^ parts sand: 4 3^ parts stone, add 12 per cent hydrated lime. "For 1 part Portland cement: 3 parts sand: 5 parts stone, add 16 per cent hydrated lime. "These percentages are based on the weight of the dry hydrated lime to the weight of the dry Portland cement. " (3) The cost of large waterproof concrete structures frequently may be reduced by employing leaner proportions of concrete with hy- drated lime admixtures, and small structures, such as tanks, may be made more water-tight. " (4) Lime paste made from a given weight of hydrated lime oc- cupies about 2 J4 times the bulk of paste made from the same weight of Portland cement, and is therefore very efficient in void filling. 75 5 "i < e- \ I I I 1 a 3 H 03 tJ g 5 2 S ^3 ^ E& "Although the character of the sand and stone used in the concrete will affect the best percentage of lime to use, the present materials are representative of average materials throughout the country so that the results should be of general application. Coarser sand would naturally require slightly larger percentages of lime and finer sand, that is, sands having a larger percentage of fine grains, which pass a sieve with 40 meshes to the linear inch, would be apt to require less lime since sands containing considerable fine material produce a more water-tight al- though a weaker concrete." In these experiments of Thompson a water pressure of 60 pounds to the square inch was used, which is equivalent to a head of about 140 feet. This is more severe than is encountered in the general engineering practice. The conclusions to be drawn from the investigations given indicate that in hydrated lime we have the best material at present known for rendering concrete water-tight. Hydrated lime,] however, must not be confounded with quick-lime, which is absolutely unfit to be used in concrete. The effect of the addition of hydrated lime in small quantities is mostly mechanical, filling the voids, thus making the concrete imper- vious to water. The quantity which should be used depends upon the fineness of the sand employed and the proportions of the mixture. The concrete materials must be properly graded, the proper proportions of cement and hydrated lime used. Even with this preliminary care, if the concrete is poorly mixed with insufficient water, or improperly placed, or if joints are left, the walls will inevitably leak. The mixing must be thorough; sufficient water must be employed to give a " mushy '* mixture so that it will settle into place with the least amount of ramming. Fully as important as the care in mixing is the bonding of one day's concrete with the next; even small interruptions of an hour on a hot day will materially injure the bond of the concrete. It is, therefore, necessary that if water-tight work is to be done, the greatest care should be exer- cised both in the selection of the materials, proportions of the ingredients, mixing and placing the same. Hydrated lime can be advantageously used only in mixtures as lean or leaner than 1-2-4 unless the hydrated lime is substituted for an equal weight of cement. Ten per cent by weight of the cement has been found a convenient amount in a number of instances. Hydrated lime is a bulky material, the same weight oc- cupying about two and one-half times the volume of the same weight of cement. 77 HOTEL OREGON, PORTLAND, OREGON DOTLE-l'ATTERSON, ARCHITECTS Hydrated Lime Used in Concrete and Brick Mortar ADVANTAGES OF HYDRATED LIME OVER OTHER FORMS OF LIME. CHAPTER X HYDRATED lime is generally purer than the quick lime from which I it is made. Chapter VIII, Page 50. Hydrated lime is easily subjected to inspection and tests, and the same material is tested as is used. Chapter VIII, Page 50. The use of hydrated lime does away with the slaking of lump lime, hence saves the cost and the space required for this operation. Chapter VIII, Page 50. Hydrated lime is thoroughly slaked and this fact can be deter- mined by tests. Chapter VIII, Page 50. By the use of hydrated lime mortar definite proportions can be maintained. This is a difficult matter with lump lime. Chapter VIII, Page 49. Table Page 53. The putty or mortar made w T ith hydrated lime requires no aging to be assured of thorough slaking. The Romans recognized the neces- sity of long aging for lime paste and an old Roman law required that lime be slaked three years before using. In the south of Europe at the present time it is the custom to slake lime the season before it is used. Chapter V, Page 38. Hydrated lime can be economically mixed by means of a mortar mixer. Chapter VIII, Page 52. Mortars made from hydrated lime are stronger than mortars made from lump lime slaked to a paste. Chapter VIII, Pages 57 to 60. Hydrated lime can be mixed with cement mortar or concrete in any desired proportions. It is a very difficult matter to mix lime paste with cement thoroughly. Chapter VIII, Page 56. Hydrated lime can be stored without danger of fire. No heat is generated when water comes in contact with hydrate. Hydrated lime is not apt to be spoiled by air slaking, as is the case with lump lime. Often large amounts of lime are lost in this manner. Hydrated lime comes into the market in packages of definite weight and convenient size. 79 The paper sacks generally used cost less than half as much as the barrels required to hold an equal weight of lump lime. The paste made from hydrated lime requires no screening. There is no loss in the form of "core" when hydrated lime is used. Against all these advantages only two objections are obvious. One, the mortar made from hydrated lime often works harder and is less plastic than that made from lump lime. This difficulty is generally greatly exaggerated. Second, hydrated lime will not carry so much sand as a corresponding weight of lump lime. This fact has been explained on page 52. The second objection is dependable upon the first, because the larger sand carrying capacity of lump lime paste is due to its plasticity, or buttery, easy working quality. This quality of lump lime usually results in the addition of too much sand. The oversanding of lime mortar is very generally practiced, since it is the custom to add as much sand as possible in order to cheapen the cost of the mortar. This results in a lean, oversanded mortar possessing little strength. The manufacturers of lime are not blameless in this respect, since they have educated the public to believe that the greater the yield of paste from a barrel of lime the more sand it will carry, overlooking the fact that a leaner lime, or one which does not yield as great a volume of paste, produces a much stronger mortar. The increase in bulk when lime is slaked is mostly due to the water mechanically absorbed. When the lime mortar hardens, this water evaporates, causing it to shrink and the excess water is therefore a source of weakness and not strength. The greater the amount of water held mechanically, the greater the volume of the paste, and therefore the less the amount of binding ingredient or lime contained in a volume of paste. This point is brought out clearly from the table on page 35. It has been proven by many experiments that the poorer limes make the stronger mortars. These poor, or lean limes contain clay, which unites with the lime during the process of burning, and the presence of this clay imparts some hydraulic or hardening properties to the mortar. These hydraulic limes are largely used in Europe, but, unfortunately, little of this material has been manufactured in this country. Practically the same results can be obtained by the use of a mixture of hydrated lime and Portland cement. From all the advantages possessed by hydrated lime it would appear to be the best form of lime to be used. It is perfectly logical that the process of slaking should be taken away from the haphazard manner used on the work and done at the point of manufacture of the lime where skillful supervision is possible. 80 APPENDIX I. Useful Data Lime. DEFINITION Lime is the product resulting from calcining (burning) of limestone, which slakes upon the addition of water. WEIGHT Lump lime weighs from 50 to 60 pounds per cubic foot. BARREL A 200 pound barrel of lime contains 185 pounds net of lump lime, or 3.1 cubic feet. A 300 pound barrel of lime contains 280 pounds net of lime or 4.7 cubic feet. BUSHEL A bushel of lime is from 75 to 80 pounds, depending upon the law in the state in which the lime is purchased. A bushel contains from 1 to 1.3 cubic feet. PASTE Lime paste is a mixture of slaked lime and water. SLAKING A pound of high calcium lime requires from 1 to 1J^ pounds of water to form a paste. A pound of dolomitic lime requires about 1 pound of water to form a paste. A barrel of high calcium lime requires from 30 to 40 gallons of water to produce a paste. A barrel of dolomitic lime requires from 25 to 30 gallons of water to produce a paste. SLAKING Slaking is the most important operation in preparing mortar. BURNING Lime must not be burned in slaking. Burning results from the use of too little water or insufficient mixing during slaking. DROWNING Lime must not be drowned in slaking. Drowning results from the use of too much water. AGING Lime used for plastering should be slaked at least 3 weeks before using. The longer the paste is aged the better the quality of the mortar. VOLUME OF PASTE A barrel of lime gives from 6 to 9 cubic feet of paste; average about 7^ cubic feet. Hydrated Lime. DEFINITION Hydrated lime is a dry, specially prepared slaked lime. WEIGHT Hydrated lime weighs from 36 to 45 pounds per cubic foot; average about 40 pounds. 81 SACK A 100 pound sack of hydrated lime contains about 2J/2 cu- bic feet. PASTE It requires about an equal weight of water to produce a paste. A 100 pound sack of hydrate gives about 2.3 cubic feet of paste of ordinary consistency. Portland Cement. DEFINITION Portland cement is made from a mixture of materials containing lime and clay. WEIGHT A barrel of Portland cement weighs 376 pounds net, and contains 3.8 cubic feet. A bag of Portland cement weighs 94 pounds and contains about 1 cubic foot. PACKED Packed cement weighs on the average 115 pounds to the cubic foot. LOOSE Loose Portland cement weighs on the average 92 pounds to the cubic foot. CUSTOMARY WEIGHT In general a sack of cement is considered to be 1 cubic foot and to weigh 100 pounds. PASTE Cement paste is a mixture of cement and water. WEIGHT OF PASTE Cement paste weighs about 137 pounds to the cubic foot. Sand. QUALITY The quality of sand is chiefly dependent upon the coarseness and the relative size of the grains. CLAY OB LOAM Clay or loam in sand is often injurious to mortar because too much fine material is introduced. SPECIFIC GRAVITY Specific gravity of sand is about 2.65. WEIGHT Sand weighs from 80 to 120 pounds to the cubic foot, average about 100 pounds. COARSE SAND Coarse sand requires less water than fine sand and gives a stronger mortar. MIXED SAND Mixed sands usually weigh more and contain a smaller volume of voids than coarse or small sands. FINE SAND Fine sand with grains of uniform size weighs nearly the same when dry and has nearly the same percentage of voids as screened sand. Fine sand with ordinary moisture is lighter and more porous than coarse sand. VOIDS Voids are the spaces in a mass of sand or mortar that are filled with water or air. 82 VEGETABLE MATTER Even a small amount of vegetable matter present in sand may result in a weak mortar. Mortar. DEFINITION Mortar is a mixture of sand and water with some binding material, such as lime, cement, or both. STRONGEST MORTAR Is obtained from those sands which produce the smallest volume of plastic mortar. FINE SANDS Always produce a mortar of less strength than coarse sands. MIXTURES OF FINE AND COARSE SANDS Often produce a stronger mortar than either material alone. CLAY OR LOAM In sand generally weakens a rich mortar and may strengthen a lean mortar. WEIGHT The weight of lime or cement mortar varies with the proportions as well as with the materials of which it is composed. Average weight of lime mortar is about 120 pounds per cubic foot. Average weight of 1-3 cement mortar is 135 pounds per cubic foot. PROPORTIONS Proportions must be accurately measured. MIXING Mixing must be thorough. All mortars are improved by long mixing. MACHINE MIXING Machine mixing is better than hand mixing and gives more plastic mortar. Quantities. AVERAGE WOODEN WHEELBARROW LOAD of broken stone is about 2.4 cubic feet. AVERAGE WOODEN WHEELBARROW LOAD of sand is about 2J/2 cubic feet. AVERAGE IRON WHEELBARROW LOAD of stone or gravel is about 3 cubic feet. AVERAGE IRON WHEELBARROW LOAD of sand is about 3j/ cubic feet. SHOVEL A No. 2 shovel holds about 15 pounds of sand. A No. 3 shovel holds about 18 pounds of sand. A No. 4 shovel holds about 20 pounds of sand. BUCKET A 3 gallon (12 quart) bucket holds 16 pounds of hydrata. A 3 gallon (12 quart) bucket holds 35 pounds of sand. A 3 gallon (12 quart) bucket holds 40 pounds of cement. 88 APPENDIX II. Standard Specifications for Hydrated Lime* SERIAL DESIGNATION: C6-15. The specifications for this material are issued under the fixed designa- tion C6; the final number indicates the year of original issue, or in the case of revision, the year of last revision. ADOPTED, 1915. 1. DEFINITION. Hydrated lime is a dry flocculent powder resulting from the hydration of quicklime, 2. CLASSES. Hydrated lime is commercially divided into four classes: (a) High- Calcium ; (b) Calcium; (c) Magnesian ; (d) High-Magnesian. 3. BASIS OF PURCHASE. The particular class of hydrated lime desired shall be specified in advance by the purchaser. I. CHEMICAL PROPERTIES AND TESTS. 4. SAMPLING. The sample shall be a fair average of the shipment. Three per cent of the packages shall be sampled. The sample shall be taken from the surface to the center of the package. A 2-lb. sample to be sent to the laboratory shall immediately be transferred to an air-tight container, in which the unused portion shall be stored until the hydrated lime has been finally accepted or rejected by the purchaser. 5. CHEMICAL PROPERTIES. (a) The classes and chemical properties of hydrated lime shall be determined by standard methods of chemical analysis. (b) The non- volatile portion of hydrated lime shall conform to the following requirements as to chemical composition: 'Authorized reprint from the copyrighted Year Book for 1915 of the American So- ciety for Testing Materials, Philadelphia, Pa. , U. S. A. 84 CHEMICAL COMPOSITION Properties Considered. High- Calcium Calcium Magnesian High- Magnesian Calcium Oxide per cent 90 (min.) 85-90 Magnesium Oxide per cent. . 10-25 25 (min ) Silica plus Alumina plus Oxide of Iron max per cent. . 5 5 5 5 Carbon Dioxide, max., per cent 5 5 5 5 \Vater Sufficient to Sufficient to Sufficient to Sufficient to hydrate the hydrate the hydrate the hydrate the calcium- calcium- calcium- calcium- oxide oxide oxide oxide content content content content II. PHYSICAL PROPERTIES AND TESTS. 6. FINENESS. A 100-g. sample shall leave by weight a residue of not over 5 per cent on a standard 100-mesh sieve and not over 0.5 per cent on a standard 30-mesh sieve. 7. CONSTANCY OF VOLUME. Hydrated lime shall be tested to deter- mine its constancy of volume in the following manner: Equal parts of hydrated lime under test and volume-constant Portland cement shall be thoroughly mixed together and gauged with water to a paste. Only sufficient water shall be used to make the mixture workable. From this paste a pat about 3 in. in dia- meter and J/-2 in. thick at the center, tapering to a thin edge shall be made on a clean glass plate about 4 in. square. This pat shall be allowed to harden 24 hours in moist air and shall be without pop- ping, checking, cracking, warping or disintegration after 5 hours* exposure to steam above boiling water in a loosely closed vessel. III. PACKING AND MARKING. 8 . PACKING. Hydrated lime shall be packed either in cloth or in paper bags and the weight shall be plainly marked on each package. 9. MARKING. The name of the manufacturer shall be legibly marked or tagged on each package. IV. INSPECTION AND REJECTION. 10. INSPECTION. (a) All hydrated lime shall be subject to inspection. (b) The hydrated lime may be inspected either at the place of manufacture or the point of delivery, as arranged at the time of purchase. 85 (c) The inspector representing the purchaser shall have free entry at all times while work on the contract of the purchaser is being performed, to all parts of the manufacturer's works which concern the manufacture of the hydrated lime ordered. The manu- facturer shall afford the inspector all reasonable facilities for inspec- tion and sampling, which shall be so conducted as not to interfere unnecessarily with the operation of the works. (d) The purchaser may make the tests to govern the acceptance or rejection of the hydrated lime in his own laboratory or elsewhere. Such tests, however, shall be made at the expense of the purchaser. 11. REJECTION. Unless otherwise specified, any rejection based on failure to pass tests prescribed in these specifications shall be re- ported within five working days from the taking of samples. 12. REHEARING. Samples which represent rejected hydrated lime shall be preserved in air-tight containers for five days from the date of the test report. In case of dissatisfaction with the results of the tests, the manufacturer may make claim for a rehearing within that time. APPENDIX III. QUANTITIES OF MATERIALS FOR ONE CUBIC YARD OF PLASTIC MORTAR HYDRATED LIME MORTAR One bag of hydrate equals 100 pounds, 2^ cubic feet TABLE No. 1 PARTS BY VOLUME Proportions Parts Proportions By Volume Volume of Mortar from One Bag Quantities of Materials to Make 1 Cubic Yard of Mortar Hydrate Sand Hydrate Bags Sand Cu. Ft. Cu. Ft. Hydrate Bags Sand Cu. Yds. 1 2.50 3.44 7.84 0.73 IX 2 3.75 5.00 4.61 5.79 5.85 4.66 0.81 0.86 2j^ 6.25 6.97 3.87 0.89 3 7.50 8.15 3.31 0.92 3% 8.75 9.32 2.90 0.94 4 10.00 10.50 2.57 0.95 43^ 11.25 11.67 2.31 0.96 5 1 12.50 12.85 2.10 0.97 NOTES Variations in the fineness of the sand and in the consistency of the mortar may affect the yield of mortar by 10% in either direction. Hydrated Lime requires about its own weight of water to be reduced to a paste. The volume of this paste is about 90% of the volume of dry hydrate. The volume of mortar refers to its volume in a plastic condition as mixed, not to its volume after ramming or hardening. TABLE No. 1-A PARTS BY WEIGHT Proportions By Parts Proportions By Volume Volume of Mortar from One Bag Quantities of Materials to Make 1 Cubic Yard of Mortar Hydrate Sand Hydrate Bags Sand Cu. Ft. Cu. Ft. Hydrate Bags Sand Cu. Yds. 1 1 1 1 1 1 1 1 1 1 IX 2 &A 3 &A VA 5 1 IX 2 VA 3 3^ 4 4^ 5 2.00 2.46 2.94 3.44 3.89 4.37 4.83 5.31 5.79 13.50 10.96 9.19 7.84 6.93 6.17 5.59 5.08 4.66 0.50 0.61 0.68 0.73 0.77 0.80 0.83 0.85 0.86 87 QUANTITIES OF MATERIALS FOR ONE CUBIC YARD OF PLASTIC MORTAR. HYDRATED LIME MORTAR WITH ADDITION OF PORTLAND CEMENT. TABLE No. 2 PARTS BY VOLUME Proportions Proportions Pounds of Portland Cement by For One Cubic Yard Required for Each Per Cent. Added Parts by Volume Hydrate Sand 5% 10% 15% 20% 25% Hydrate Sand Bags Cu. Yds. Lbs. Lbs. Lbs. Lbs. Lbs. 2 4.66 0.86 23 46 70 92 115 2j^ 3.87 0.89 19 39 58 78 97 3 3.31 0.92 16 32 48 64 83 3/^2 2.90 0.94 15 29 43 58 72 4 2.57 0.95 14 27 40 51 64 1 4/^ 2.31 0.96 12 23 35 46 58 1 5 2.10 0.97 11 22 33 44 54 NOTES Variations in the fineness of the sand and in the consistency of the mortar may affect the yield of mortar by 10% in either direction. The amount of Portland cement added is a percent of the amount of Hydrate used. A cubic foot of dry hydrate weighs 40 Ibs. A cubic foot of Portland cement weighs 100 Ibs. TABLE No. 2-A PARTS BY WEIGHT Proportions by Parts Proportions For One Cubic Yard by Volume Pounds of Portland Cement Required for Each Per Cent. Added Hydrate Sand Hydrate Bags Sand Cu. Yds. 5% Lbs. 10% Lbs. 15% Lbs. 20% Lbs. 25% Lbs. 1 1 1 1 1 1 1 2 V/2 3 3K 4^ 5 9.19 7.84 6.93 6.17 5.59 5.08 4.66 .68 .73 .77 .80 .83 .85 .86 46 39 35 31 28 25 23 92 78 69 62 56 51 47 138 118 104 93 84 76 70 184 157 139 123 111 102 93 230 196 173 154 140 127 116 88 QUANTITIES OF MATERIALS FOR ONE CUBIC YARD OF PLASTIC MORTAR. CEMENT MORTAR WITH HYDRATED LIME ADDITIONS. TABLE No. 3 Volume Proportions by Parts, Weight Proportions by Re- sulting Quantities to Make 1 Cubic Pounds of Hydrate Required for Each Percent or Volume Volume Mortar Yard of Added Cu. Ft. Mortar From C ement Sand Cement Sand 1 Bbl. Cement Sand 5% 10% 15% 20% 25% Bbls. Cu. Ft. Cement Bbls. Cu. Yd. Lbs. Lbs. Lbs. Lbs. Lbs. 1 2 1 7.6 10.0 2.70 .76 50 101 151 202 252 1 2^ 1 9.5 11.8 2.29 .81 43 86 129 172 215 1 3 1 11.4 13.7 .97 .83 38 74 111 148 186 1 SH 1 13.3 15.5 1.74 .86 32 65 97 130 162 1 4 1 15.2 17.3 1.56 .88 29 58 87 116 145 1 4^ 1 17.1 19.1 1.41 .89 26 53 79 106 132 1 5 1 19.0 21.0 1.28 .90 24 48 72 96 120 NOTE Variations in the fineness of the sand and in the consistency of the mortar may affect the yield of mortar by 10% in either direction. The amount of Hydrated Lime is a percent of the amount of Portland cement used. QUANTITIES OF MATERIALS FOR ONE CUBIC YARD OF PLASTIC MORTARS HYDRATED LIME-PORTLAND CEMENT MORTAR Equal Parts of Hydrate and Cement TABLE No. 4 PARTS BY VOLUME Proportions Volume of Quantities of Materials by Proportions by Mortar from to Make 1 Cubic Yard Parts Volume 1-40 Ib. Bag TT -J_~J-^ OM/J 1 Hydrate Cement 100 Ib. Bag Hydrate Cement Sand Hy- Ce- 40 Lbs. 100 Lbs. Sand Cement 40 Ib. 100 Ib. Cu. Yd. drate ment Sand Bag Bag Cu. Ft. Cu. Ft. Bag Bag 1 1 3 3 4.18 6.46 6.46 0.72 1 1 4 4 5.13 5.26 5.26 0.77 1 1 5 5 6.08 4.44 4.44 0.82 1 6 6 7.03 3.84 3.84 0.85 1 7 7 7.98 3.38 3.38 0.87 1 8 8 8.93 3.02 3.02 0.89 1 9 9 9.88 2.73 2.73 0.91 1 10 10 10.83 2.49 2.49 0.92 NOTE Variation in the fineness of the sand and in the consistency of the mortar may affect the yield of mortar by 10% in either direction. The volume of mortar refers to its volume in a plastic condition as mixed, not to its volume after ramming or hardening. 89 QUANTITIES OF MATERIAL FOR ONE CUBIC YARD OF RAMMED CON- CRETE SHOWING ALSO THE AMOUNT OF HYDRATED LIME ADDED TABLE No. 5 Proportions by Parts Proportions by Volume Quantities for One Cubic Yard Pounds of Hydrated Lime Added for One Yard Mixture Cement Sand Stone Cement Bbls. Sand Cu. ft. Stone Cu. ft. Cement Bbls. Sand Cu. yd Stone Cu. yd 5% Ibs. 10% Ibs. 15% Ibs. 20% Ibs. 25% Ibs. 1 1 1 2 2H 3 1 1 1 3.8 3.8 3.8 7.6 9.5 11.4 2.73 2.45 2.20 0.38 0.34 0.31 0.77 0.86 0.94 51 46 41 103 92 83 154 138 124 206 184 165 257 230 206 VA l l /2 iy 2 2 &A 3 1 1 1 5.7 5.7 5.7 7.6 9.5 11.4 2.40 2.18 2.00 0.51 0.46 0.42 0.68 0.77 0.84 45 41 37 90 82 75 135 123 113 180 164 150 225 205 188 2 2 2 2 3 3^ 4 4^ 1 1 1 1 7.6 7.6 7.6 7.6 11.4 13.3 15.2 17.1 1.81 1.68 1.57 1.48 0.51 0.47 0.44 0.42 0.76 0.83 0.88 0.94 34 31 29 28 68 63 59 56 102 94 88 84 136 125 117 112 170 156 146 140 &A &A &A &A &A &A VA 3 3>i 4 4^ 5 5^2 6 1 1 1 1 1 1 1 9.5 9.5 9.5 9.5 9.5 9.5 9.5 11.4 13.3 15.2 17.1 19.0 20.9 22.8 1.66 1.55 .46 .37 .30 .23 .17 0.58 0.55 0.51 0.48 0.46 0.43 0.41 0.70 0.76 0.82 0.87 0.92 0.95 0.99 31 29 27 26 24 23 22 62 58 55 52 49 46 44 93 87 82 78 73 69 66 124 116 110 104 96 92 88 155 145 137 130 123 115 110 127 120 115 110 105 100 95 90 87 1 1 1 1 1 1 1 1 1 3 3 3 3 3 3 3 3 3 4 4^ 5 5^ 6 6^ 7 7^ 8 11.4 11.4 11.4 11.4 11.4 11.4 11.4 11.4 11.4 15.2 17.1 19.0 20.9 22.8 24.7 26.6 28.5 30.4 .36 .28 .22 .16 .11 .06 .01 0.97 0.93 0.57 0.54 0.52 0.49 0.47 0.45 0.43 0.41 0.39 0.77 0.81 0.86 0.90 0.94 0.97 0.99 1.02 1.05 25 24 23 22 21 20 19 18 17 51 48 46 44 42 40 38 36 35 76 72 69 66 63 60 57 54 52 102 96 92 88 84 80 76 72 70 1 1 1 1 1 1 4 4 4 4 4 4 5 6 7 8 9 10 15.2 15.2 15.2 15.2 15.2 15.2 19.0 22.8 26.6 30.4 34.2 38.0 1.08 0.99 0.92 0.85 0.80 0.75 0.61 0.56 0.52 0.48 0.45 0.42 0.76 0.84 0.91 0.96 1.01 1.06 20 18 17 16 15 14 40 37 34 32 30 28 60 55 51 48 45 42 80 74 68 64 60 56 100 92 85 80 75 70 1 5 10 1 19.0 38.0 0.69 0.49 0.97 13 26 39 52 65 NOTES The above table for quantities of cement has been taken from Taylor & Thomp- son's "Concrete, Plain and Reinforced." The quantities of hydrated lime have been cal- culated by the author. In many instances the amounts are even fractions of a sack of hydrate (100 Ibs.), i. e., 10% in a 1-2-4 is practically half a sack. In case where the amount of hydrate called for is not a convenient part of a sack, it is advisable to have a box made which will hold the required amount. This is easily done, as a cubic foot of hydrate weighs 40 Ibs. A one sack mixture would require the addition of % the amount of materials and a 2 sack mixture of ^ the amount. 90 INDEX SUBJECT Page Aluminum 1213 Arenaceous Limestone 21 Argillaceous Limestone 21 Atom 11 Atomic Weights 12 B Barrel 81 Basic Carbonate , 38 Brigham, S. Y 42 Brewer, Bertram 74 Bucket Size 83 Burning, Chemical change 14 Bushel 81 C Calcium 12-13 Carbon 12-13 Carbonates 13 Cement Hydrated Lime Mortar Quantities 89 Chalk 21 Chapman, Cloyd M 35 to 37 Chemistry of Lime 11 to 20 Chemical Symbols 12 Classification 21 Coal 31 Composition Calculation 18-19 Compound 11 Concrete Cracking 66 Concrete Quantities of Materials 90 Concrete Water Proofing 70 to 77 Conglomerate Limestone 21 D Dolomite Limestone 21 91 SUBJECT p age E Edfou 10 Egypt 9 Eldred Process 31 Element 1 1 Emley, Warren E 37-56 Etruscans ; ; . . 10 F Fue 1 .....;...... 30 G Greeks 10 H Hardening Chemical Change 16 High Calcium Limestone 21 Historical 9-10 Hydrate Calculating Composition 19 Hydrated Lime 22 Hydrated Lime Advantage of 49 to 53-79-80 Hydrated Lime Cement Mortar Quantities 87 Hydrated Lime Chemical Composition 46 Hydrated Lime Definition 41-81 Hydrated Lime Manufacture of 41 to 45 Hydrated Lime Mortar Quantities . 87 Hydrate Paste . 82 Hydrated Lime Properties of 46 to 48 Hydrated Lime Physical Properties 47-48 Hydrated Lime Specific Gravity 47 Hydrated Lime Specification 84 Hydrated Lime Use in Concrete 63 to 77 Hydrated Lime Use of 49-50 Hydrated Lime Weight 47-81 Hydrates 13 Hydrating Chemical Change 15 Hydrating Dodge Process 42 Hydrating Modern Methods of 42 Hydrating Clyde Process 42-43 Hydrating Kritzer Process 43-44 Hydrating Pierce Process 42 Hydrating Reaney Process 43 Hydrating Lauman Process 45 Hydraulic Lime 22 Hydrogen 12-13 Hydroxides 13 92 SUBJECT Page I Iron 12-13 J Jackson, Chas. T 25 to 27 K Kiln Aalborg 30 Kiln Continuous 24-26 Kiln Draw 26-27 Kiln Field 25-26 Kiln Intermittent 24 Kiln Pot 24-25-26 Kiln Producer Gas . 31 to 32 Kiln Ring 26 Kiln Rotary 26-30 Kiln Schofer 30 Kiln Steel Encased 28 to 30 Kilns Types 24 Kiln Vertical 26-28 to 30 L Lazell, E. W 56-72-73 Lime Calcium 22 Lime Chemistry 11 to 20 Lime Classification of 21 to 23 Limestone Classes of 21 "Lime Cycle" 16-17 Lime Definition 22-84 Lime Fat 23 Lime Ground 22 Lime High Calcium 22 Lime High Magnesium 22 Lime Hydrated 22 Lime Hydraulic 23 Lime Hydraulic Definition 22 Lime Lean 23 Lime Magnesium 22 Lime Manufacture of 24 to 33 Lime Overburned 38 Lime Paste 81 Lime Paste Aging 38 Lime Paste Volume 81 Lime Paste Water in 36-37 93 SUBJECT p age Lime Pulverized 22 Lime Run of Kiln 22 Lime Selected Lump 22 Lime Slaking 34 to 40 Lime Types 22 Lime Weight 81 Limestone Composition 21 Limestone -Definition 21 Limestone Origin 21 M Magnesium 12-13 Magnesium Limestone 21 Marble 21 Marl 21 Mass 11 Miller 9 Molecular Weight 12 Molecule 11 Mortars 49 to 62 Mortar Brick or Tile 54-55 Mortar Cement Lime 56 to 62 Mortar Definition 83 Mortar Hydrated Lime Quantities 87 Mortar Metal Lath 54 Mortar Mixing Machine 52 Mortars Specifications 53-54-55 Mortar Strength of 56 to 60 Mortar Tests of 57 to 60-72 to 75 Mortar Wood Lath 53-54 Mortar Weight 83 Ombos 10 Oolite 21 Oxides 13 Oxygen 12-13 Oxy-hydrate 38 P Palladius 10 Permeability Tests 72 to 75 Plasterers Co 10 Plastic Definition 63 Plasticity Concrete 63-66 Pliny 10 Portland Cement Barrel 82 94 SUBJECT Page Portland Cement Definition 82 Portland Cement Paste 82 Portland Cement Weight 82 Producer Gas 31 Pyramids 9 Pyramids Cheops 10 R Romans ^ .................. 10 8 Sack Hydrate , 82 Sand Quality Sand Specific Gravity 82 Sand Specifications for 52 Sand Weight 82 Sand Voids 82 Shovels Size 83 Silicon 12-13 Slaking "Burned" in 34-37-81 Slaking Chemical Change 15-34-81 Slaking Chemical Changes 34 Slaking Drowned 35-81 Slaking Dry Methods 41 Slaking Italian Method 39 Slaking Methods of 34 Slaking Roman Method 38 Slaking Water Required 35-36-37-81 Specification Cement Hydrate Mortar 62 Stucco 10 Sulphur 12-13 T Thomaston, Me 25-26 Thompson, Sanford E 74-75 r Vicat 9 Vitruvius 10-38 W Wheelbarrows Size 83 Woolson, Ira H 56 Wright, W. 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